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News and views (1&2) AAPPS Bulletin (2023) 33:6 AAPPS Bulletin AAPPS Bulletin https://doi.org/10.1007/s43673-023-00075-6 Open Access NE W S AND VIE W S 2022 Nobel Prize in Physics; 53rd AAPPS Council Meeting; 2022 Nishina Memorial Award; 2023 JPS Award AAPPS Bulletin Prize in physics? We try to provide some interpretations 1 2022 Nobel Prize in physics: Bell inequalities of these results. and quantum entanglement by Shang‑Shu Li and Heng Fan 1.2 Quantum entanglement and EPR paradox 1.1 Background It all starts with the mysterious quantum entanglement. Three physicists, Alain Aspect, John F. Clauser, and In 1935, Schrödinger found that under the framework Anton Zeilinger, are awarded the Nobel Prize in physics of quantum mechanics, there would be such a quantum in 2022 for “Experiments with entangled photons, estab- state that the wave functions of two particles could not be lishing the violation of Bell Inequalities and pioneering written as the direct product of the wave functions of sin- quantum information science.” This will undoubtedly add gle particles. Namely, the wave function of two particles impetus to the development of new quantum technol- cannot be separated, and we could only use the whole ogy. Anders lrback, Chairman of the Nobel Committee wave function to describe the two-particle state. This for Physics, pointed out that “The laureates’ work with property seems not to be strange. However, when tak- entangled states is of great importance, even beyond ing account of the quantum mechanics statements about the fundamental questions about the interpretation of measurement and spatial locality, it would lead to the quantum mechanics.” It can be understood that the basic EPR (Albert Einstein, Boris Podolsky, and Nathan Rosen) mechanism and principles of quantum computing and paradox [1] that confuses a lot of people. Consider that quantum information processing are based directly on we can prepare a special entangled state, in which each this year’s Nobel Prize work. particle can be measured to two states: “ + ” and “ − .” In recent years, quantum technology has become According to theory that wave function collapses, in such one of the commanding heights of scientific and tech - an EPR state, when we find the first particle as “ + ” in nological competition. A lot of countries around the measurement, the second particle must be measured as world have invested huge resources in quantum com- “ − ” and vice versa. Note, however, that the collapse of puting, quantum metrology, quantum communication, the wave function in quantum mechanics is instantane- and other quantum technological areas. On the other ous. Even if we separate the two particles sufficiently far hand, quantum mechanics has always been of interests away, the measurement of one particle can also immedi- for public. People usually use quantum mechanics con- ately determine the result of other. It is as if there exists cepts such as “quantum entanglement” and “Schröding- an interaction with speed exceeding the speed of light er’s cat” to describe some daily phenomena in Internet. (action at a distance). This result has been absurd to most So, what is the meaning of quantum entanglement, and people, even Einstein and the co-authors, hence named why did the experiments on Bell’s inequality win Nobel “EPR paradox.” Einstein believed that the world is local or realistic or both, where “local” means that no influence *Correspondence:Association of Asia Pacif, ic Physical Societies, Pohang, can be generated beyond the speed of light, while reality South Korea describes the objective existence of a physical element, © The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/. AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 2 of 12 and our measurements are all derived from this physi- and its value can bex andx . Bob also has two ways of 0 1 cal reality and cannot affect it. But in quantum mechan - measuring y, labeled asy and y . Moreover, it is assumed 0 1 ics, when we make a measurement, the wave function that the measurement can only obtain two outcomes: − 1 will collapse immediately, and the single-shot measure- and + 1. Here, we use a to represent the measured results ment result is random, even still constrained by the cor- of Alice and b for that of Bob. Then after many measure - responding amplitudes. To illustrate this issue, Einstein ments, we can find two facts: (1) when the measurement et al. argued that this result of quantum mechanics is due basis is fixed, the results can present a certain probabil - to that its theory is incomplete. ity distribution. For example, when Alice measures x and This incompleteness is manifested in the hidden varia - Bob measuresy , the values of a and b are always oppo- ble theory proposed by Boehm in 1952 [2]. In this theory, site. When Alice measures x and Bob measuresy , there 1 0 quantum mechanics is still local-realistic, and the EPR is no such correlation, and the probabilities of b to get + 1 paradox is caused by our ignorance of hidden variables. and − 1 are equal. In general cases, we can define the To understand hidden variables, let us take a daily exam- probability distribution of measurement outcomes. Here, ple. Suppose Alice has a pair of shoes, and she will give we use p abxy to represent the joint conditional prob- them to two people who are far apart from each other, ability distribution of outcomes when the measurement Bob and Charlie. Alice has told them there is only one axes are x andy . (2) No matter how far Alice and Bob are pair of shoes. Now, when Bob opens his package, he can from each other, their measurement results always show determine immediately whether Charlie’s shoe is left or correlation, that is as follows: right, which seems to be much like quantum entangle- p abxy ≠ p(ax)p by (1) ment. However, on second thoughts, it is clear that this is not an action at a distance; it is just because Bob knows In the previous section, we mentioned that if the meas- the implicit condition: there is only one pair of shoes. It urement depends on some hidden variable, the results is that implicit condition that makes relevant of Bob and will show a correlation. Let us think about the fact that Charlie’s results. Quantum mechanics in Boehm’s theory we have a variable  in addition. We cannot observe it is more like that the world is still local-realistic, but the for some physical reason, and the value of  can vary in condition such as “one pair of shoes” is not known; per- each measurement. Suppose it also satisfies a probability haps in the EPR case, the separation of the two particles distribution q(λ) . The measurement distribution of Alice has already been determined to be opposite by hidden and Bob is now determined by two variables, which are variables, rather than by the action at a distance in meas- denoted by p(ax, λ) and p by, λ , respectively. What uring. The question then becomes how can we know does the joint probability look like? If we introduce the whether quantum mechanics is described by hidden vari- local condition, the results of Alice and Bob cannot affect ables? That is what Bell’s inequalities solve. each other, and then, the joint probability must be the product form as follows: 1.3 Bell’s inequalities p abxy,  = p(ax, λ)p by, λ The significance of Bell’s inequality is to transfer the (2) problem of whether the world is local-realistic into a Note that under this assumption, due to our ignorance mathematical formula. And, we can test it by designing of the hidden variable  , the observation results average specialized physical experiments. The key to solve the over possible values of  ; the observation results can then problem is that the correlation generated by local hid- be correlated, i.e., as follows: den variable theory has a bound. If this bound is violated, the world is not described by the local hidden variables; p abxy = q()p(ax, )p by, quantum mechanics is complete but nonlocal. The first Bell inequality was proposed by Bell in 1964 [3], and many similar inequalities have been developed in similar ≠ q()p(ax, ) q()p by, � � framework. The Nobel Prize of physics in this year was = p(ax)p by awarded for a series of experiments, such as those veri- fied the violation of Clauser, Home, Shimony, and Holt Equation ( 2 ) is the joint probability distribution (CHSH) inequalities [4]. obtained under the local hidden variable theory. It can CHSH inequality, consider that Alice and Bob are sep- be seen that Alice’s (Bob’s) measurement results only arated by a certain distance, and each has a particle. The depend on the local variable x(y) and the hidden variable state of these two particles may be described by quantum . However, in quantum mechanics, Alice’s measurement mechanics or by hidden variable theory. Suppose Alice results are correlated with that of Bob in some way, so measures the particle in two ways. Let us label it withx , AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 3 of 12 that the joint probability of quantum mechanics may be the correlation function in CHSH inequality can be given beyond the expression ability of formula ( 2 ). Now let us by simple vector multiplication as follows: try to figure out the limitation of the expression under √ √ � � � � � � � � E a , b + E a b + E a , b = 1∕ 2, E a , b =−1∕ 2 localize hidden variable theory, which is Bell’s inequality. 0 0 0 1 1 0 1 1 (5) Let us consider the relationship between the expecta- tions of measurement results, under specified measure - It follows that S = 2 2 > 2 , meaning that quantum ment axes. Define the correlation function as follows: mechanics indeed violate the CHSH inequality. E a , b = p abxy ab x y 1.4 Experimental verification (3) a,b Although Bell inequality is such a simple mathematical formula, experimental verification remains challenging. Furthermore, define the observable S = E a , b + 0 0 First of all, it requires that the entangled states are pre- E a b + E a , b − E a , b . Due to the exist- 0 1 1 0 1 1 pared with high fidelity experimentally and separated at ence of formula ( 2 ), formula ( 3 ) can be written a sufficiently long distance. The experimenter needs to as the sum of product of local expectation value, make sure that the transmission of information below under the distribution of implicit variable, namely or equal the speed of light is excluded when measuring E a , b = ∫ q(λ)E a ;λ E b ;λ . The local expecta - x y x y � � λ the two particles. The second challenge is the ability to tion E a ;λ = ap(a�x, λ) is in the interval [− 1, 1], the measure particles in different arbitrary directions, since same for E b ;λ . only in certain directions quantum mechanics can vio- Now, we have the following: S = dq(λ) E a ;λ E b ;λ + E b ;λ + E a ;λ E b ;λ − E b ;λ 0 0 1 1 0 1 ≤ dq(λ)E b ;λ + E b ;λ  + E b ;λ − E b ;λ 0 1 0 1 ≤ dq λ 2 ≤ 2 ( ) We then obtain the famous CHSH inequality, late Bell’s inequality. In addition, the particle detection efficiency of the detector will also affect the verification S = E a , b + E a b + E a , b − E a , b ≤ 2 0 0 0 1 1 0 1 1 of Bell inequality. Therefore, historically, the verification (4) of Bell’s inequality has been carried out in the process of It is a variation of the original Bell inequality. In other constantly closing the loopholes. words, under the probability distribution obtained by the In 1972, John F. Clauser and Stuart Freedman per- local hidden variable hypothesis, the value of the correla- formed the first Bell experiment [5]. They used the cas - tion function S must satisfy this inequality. If the actual cade transition of calcium atoms to produce entangled measurement results violate this inequality, it means photon pairs. However, because the photon pair genera- that the real world cannot be described by local hidden tion efficiency is very low, the measurement time reaches variable theory. So, does quantum mechanics violate 200  h, and the distance between the two photons is too this inequality? The answer is yes. For example, we pre - short; there is a loophole of locality. In addition, fixed pare Alice and Bob’s particle pairs into the spin singlets measurement base is also one of the reasons for criticism. ψ ⟩ = 1∕ 2(�01⟩ − �10⟩ , where �0 ⟩ and �1 ⟩ are the In 1981 and 1982, Alain Aspect and his collaborators AB eigenvectors of the Pauli operator σ . For any particle, conducted a series of experiments that improved the we can measure the eigenvalue in its quantized direc- measurement accuracy and reduced the loopholes in the �⃗ tion x ⋅ σ �⃗ in the experiment. Let the measured direc- verification of Bell’s inequality. In the first experiment [6 ], �⃗ tion of Alice be x and Bob’s be y �⃗ . Then, the value of the they used a double laser system to excite calcium atoms, correlation function obtained by quantum mechanics is producing pairs of entangled photons and improving the �⃗ −x ⋅ y �⃗ . Now, we use these results to test the CHSH ine- entanglement source. In the second experiment [7], a two- quality and let Alice’s two measurement directions be channel method was used to improve photon utilization. two orthogonal basis x =  e , x =  e . Bob’s two meas- The measurement accuracy has been greatly improved. 0 1 1 2 urement directions are also orthogonal but have an The third experiment [8 ] is the most important for closing angle with Alice’s. If Bob selects the two directions as the locality loophole. In the experiment, the two entangled √ √ � � � � y =−  e +  e ∕ 2, y = − e +  e ∕ 2 , the value of photons are separated by about 12  m, and this distance 0 1 2 1 1 2 AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 4 of 12 needs 40 ns for the signal to travel at the speed of light. The decode it by measurement (without the help of classical distance between the photons and polarizer is 6 m. When means). Second, since there is no classical communica- performing measurement, polarizer rotates for no more tion between Alice and Bob, the probability distribution than 20 ns. Using acousto-optical devices, photons can be of Alice’s measured results will not change regardless switched to two measurement bases on even shorter time of whether Bob measures or not, namely regardless of scales. The measurement time is much less than the time whether Alice’s particles collapse. Therefore, Bob’s meas - it takes for the signal to travel between two photons at the urement operation will not transmit any information to speed of light, closing the locality loophole. Alice. In quantum mechanics, this is represented by the In 1998, Anton Zeilinger’s team tested the Bell inequal- fact that the density matrix describing Alice’s particles ity under strict local conditions [9], with observers up does not change. So, does quantum entanglement make to 400  m apart, closing the locality loophole completely. any sense? Of course, the violation of Bell’s inequality Subsequently, there have been a lot of experiments on the shows that entanglement is a kind of resource that tran- violation of Bell’s inequality. They are all aimed at closing scends classical one, which indicates that even with infi - the loopholes in the verification of quantum mechanics nite classical resources, we cannot achieve the results of from various aspects, so that we are more and more con- quantum entanglement. fident in using quantum mechanics to describe the world. The research of such problems and all other efforts One interesting experiment is the Big Bell Test [10], which gave birth to the second quantum revolution which aims was designed to eliminate the effect of pseudo-random - at the processing and application of quantum informa- ness on the verification of Bell’s inequality. We know that tion. The first quantum mechanical revolution in history random numbers generated by computers in simulations happens after the establishment of quantum mechanics. or experiments are pseudo-random numbers. As long as In this revolution, various classical applications based on we give a certain seed, then the following series of random quantum principles were developed, such as laser, semi- numbers are determined. This leads to the possibility that conductor, and nuclear energy, which enabled mankind the correlation of experimental results measured in this to quickly step into the information age, while the sec- way may exceed the limit represented by Bell’s inequality. ond quantum mechanical revolution is aimed to directly So how do you get a “true” random number? Big Bell develop the applications of quantum coherence and quan- Test proposes to solve this issue by using human’s free tum entanglement in quantum mechanics. Quantum will to generate random numbers, as long as you believe information technology takes quantum bits as the basic that a person’s will is free and random. Okay, no, we do unit, and the generation, transmission, processing, and not believe it neither, maybe the experimenters have OCD detection of quantum information all follow the principle (obsessive–compulsive disorder) or something related. To of quantum mechanics. In the last decades, the develop- solve this problem, the researchers gathered more than ment of quantum computing theory and applications of 100,000 volunteers around the world and asked them to quantum communication have made us see the potential quickly and randomly press either 0 or 1 button in a game of quantum technology to change the world. On the one of tricks. They then uploaded the choices to the cloud hand, the development of quantum technology is to use and randomly sent them to different experimenters to the principles of quantum mechanics to process, transfer, use as random number generators for their experiments. and calculate quantum information; on the other hand, it Through the free will of a large number of participants, also deepens our understanding of quantum mechanics. the Big Bell experiment closed the free choice loophole in a wider scope, strongly negating the localized hidden vari- 2 53rd AAPPS video council meeting able theory. So far, quantum mechanics has been almost by AAPPS perfectly demonstrated to be complete. The 53rd Council Meeting of the Association of Asia Pacific Physical Societies (AAPPS) was held online from 1.5 The second quantum revolution 4:00 p.m. to 6:00 p.m. (UTC + 9 h) on November 28, 2022, Quantum mechanics has been verified to be correct, via a Zoom session hosted by the Asia Pacific Center for but some problems posed by non-locality need to be Theoretical Physics (APCTP). The participants were explained here. For example, can quantum entangle- Jun’ichi Yokoyama (president), Hyoung Joon Choi (vice ment transmit information faster than light? The answer president), Nobuko Naka (secretary), Gui-Lu Long (for- is no; even though it looks like that the action at a dis- mer president, ex officio member), and council members tance travels faster than light, it does not transmit any Xiu-dong Sun (the Chinese Physical Society, Beijing), information. Take the EPR pair as an example. First, since Tao Xiang (the Chinese Physical Society, Beijing), Ruiqin the collapse of the measurement is random, neither Alice Zhang (the Physical Society of Hong Kong), Rajdeep Singh nor Bob can encode the information into the EPR and Rawat (Institute of Physics Singapore), Fu-Jen Kao (the AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 5 of 12 Physical Society located in Taipei), Meng-Fan Luo (the As a nonprofit society, the budget relies on membership Physical Society located in Taipei), and Nguyen Quang fees, registration fees, publications, and donations, as Liem (Vietnam Physical Society). Present as observers support from the ministry is limited. PSI actively uses were Reza Ejtehadi (the Physics Society of Iran), Yunkyu social media, such as Instagram, Youtube, Telegram, Bang (president of APCTP), Jae-Hyung Jeon (executive and Aparat, in addition to PSI’s own website, to share director of APCTP), and Dayoung Yang (AAPPS liaison recorded meetings and events. and editorial staff member). Treasurer Keun-Young Kim Yokoyama asked about the percentage of female physi- and council members Jodie Bradby (Australian Institute of cists in PSI. Ejtehadi responded that 48% of physics Physics (AIP)), Mio Murao (the Physical Society of Japan students and 20% of faculty members are females. The (JPS)), Akira Yamada (the Japan Society of Applied Phys- graduating female students are now gaining faculty posi- ics (JSAP)), Woo-Sung Jung (the Korean Physical Society tions, and the percentage of female faculty members is (KPS)), and Kurunathan Ratnavelu (Malaysian Institute of expected to rapidly increase in the near future. Hyoung Physics) were absent. Joon Choi queried as to why PSI applied to become an (1) Secretary Naka reported the presence of 11 council associate member rather than a full member. Ejtehadi members out of 17 council members. The quorum was answered that PSI has difficulty transferring money for declared as not fulfilled. President Yokoyama informed the payment of membership because of sanctions. that we will have approval later in writing when necessary. After Ejtehadi left the Zoom room, a discussion was (2) Yokoyama opened the 53rd Council Meeting and made by the council. Yokoyama stated that the Ira- welcomed the participants. The agenda was adopted as nian physics community is large, and they are produc- prepared by the president. ing excellent research outcomes. Therefore, it would be (3) Yokoyama introduced Prof. Reza Ejtehadi, the presi- a good idea for PSI to be, for the moment, an associate dent of the Physics Society of Iran (PSI). Ejtehadi made member. Yunkyu Bang agreed that there is no reason not a brief introduction to the society for application to join to accept. However, Bang expressed his concern about AAPPS as an associate member. PSI is a non-profit and the current political environment. Although AAPPS is non-governmental organization with the aim of estab- independent of any political organization, complete sepa- lishing and strengthening scientific cooperation among ration between politics and science is becoming unclear physics researchers, physics teachers, and students stud- these days. Rajdeep Singh Rawat shared his experience ying physics. PSI is the largest and oldest professional as the president of the International Physics Olympiad and scientific society in Iran. The society was established and the research program for plasma fusion and related in 1932 and formally founded in 1963. Activities ceased energy devices in Singapore. Fu-Jen Kao wondered about after the revolution in 1979 and resumed in 1984. The the rights of associate members. Yokoyama clarified that society presently has 11,933 members, including 2463 an associate member has no voting rights at ordinary full members, 1304 associate members, 8158 student general meetings (OGMs) and cannot send any candidate members, and 10 fellows. to become council members. Kao stated that as an asso- The General Assembly is the highest decision-mak - ciate member makes no effect on decisions by the AAPPS ing body of PSI. The board of directors consist of seven Council, the political considerations should be minimal. members. A president, vice president, and treasurer are Tao Xiang suggested changing the name of “associate elected by the board of directors from among themselves. member” to “observer.” Yokoyama responded that the PSI has many branches in areas including condensed associate member status is defined in the constitution. matter physics; particle and high-energy physics; com- Yokoyama proposed to endorse the application, which putational physics; light, atomic, and molecular phys- was seconded by Long and Xiang. The proposal was ics; statistical physics and complex systems; quantum unanimously agreed upon. information; and women in physics. In PSI, there are (4) Choi reported on APPC15, held in August 2022. committees for conferences and events, publications, He explained the list of committee chairs, 14 subjects, prizes and awards, international affairs, and industrial special sessions, and the number of presentations (963 relations. Annual physics conferences have been held presentations in total, consisting of 768 parallel talks, since 1985. Branch meetings and webinars are regularly 168 posters, 15 plenary talks, and 12 special talks). The organized. PSI publishes the Iranian Journal of Physics number of registrations was slightly over 1000, and there Research and the Journal of Applied Fluid Mechanics, in were a few no-shows in the poster sessions. Presently, 30 addition to books, reports, and proceedings. As outreach manuscripts were submitted for the proceedings. The activities, PIS organizes the Physics Club, which has a manuscripts will be sent to the publisher in January 2023, 23-year history and is held monthly in 11 cities across after review and revision processes. At APPC15, there the country, and publishes online newsletters in Persian. was small input from JSAP regarding the applied physics AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 6 of 12 subjects; how to organize the applied physics session at was to serve the association, and joint publication with the next APPC should be considered. Even though spe- APCPT brought steady growth. Currently, articles are cial sessions were open to the public and two plenary published in three ways; i.e., on the website by Springer talks on Monday were open to all member societies, the Nature, AB’s direct website at www. aapps bulle tin. org, audience was not large. This information might not be and in printed form (6 issues/year). The printed copies directly useful for APPC16, which will be held in a face- are mailed every 2  months to the cooperate members to-face manner. Nevertheless, we should strive to have who have paid for the subscription. The total surplus is bigger audiences at APPCs, and we should consider how US $138, with contributions from four member societies we might open the sessions to a wider community. Choi of AAPPS to AB. The article publication charge (APC) commented that the Division of Plasma Physics organizes has been covered by APCPT last year and this year. online meetings on a large scale, where each speaker can The first article, whose APC will be paid by the author invite a free audience. directly, will appear soon. Yokoyama thanked Choi for all his efforts in making The citations of AB are recently improving, particu - APPC15 a successful meeting. Yokoyama commented larly in the fields of particle physics, nuclear physics, and that the number of submitted manuscripts for the pro- quantum information. An expected impact factor is 6 ceedings is rather small. Choi responded that submission or 7. Among 30 published articles this year with already is optional, and most of the participants would not need 61 citations, 11 are original articles compared to only 2 to provide a contribution as they did not have to travel original articles published in 2021. Therefore, the perfor - internationally. The proceedings will be published in an mance of AB in this respect is excellent. online book dedicated to APPC15. Some of the editors have been refreshed regularly, and (5) On behalf of Treasurer Keun-Young Kim, Yokoy- cooperation with Springer Nature will continue for the ama briefly reported on the financial status of AAPPS. target of 40–100 articles to be published each year until The total balance is US $67,028, in addition to the Leo 2025. Springer Nature decided to apply for indexing in Koguan Foundation’s US $36,500. The account state - SCOPUS next year, but application to the Web of Science ments include interest and the dues that 14 societies has been pending. paid for the 2022 membership. Four societies supported Yokoyama expressed his thanks for Long’s dedica- the AAPPS Bulletin (AB) with contributions of US $5000 tion. He also commented that he agrees with the plan to each. JSAP provided support of US $5000 to AAPPS for enhance the News and Views section. Bang asked about international activities, which was partially used for the the status of the article whose APC will be paid by the meetings in Nepal and Thailand. The contribution of author. Long answered that the manuscript is under revi- APCPT of US $545,360 in total is greatly appreciated and sion after the review, and publication in the December or acknowledged. Yokoyama informed that he sent 1 million February issue is expected. Bang stated that it is good to KRW, which he had received as an honorarium for writ- have this kind of article; however, maintaining the rather ing an article in AB, to the representative of the activi- strict conditions for quality control is also important. ties for physicists in Myanmar by the Division of Nuclear Kao informed about a useful database of top journals in Physics. The donation was appreciated by the representa - the world, https:// exaly. com/ journ al. tive, who is a professor at Gifu University in Japan. Yokoyama explained that according to the discussion Kao commented that any member society that does of the Editorial Board in October, the current editor- not pay membership fees has no right to vote at OGMs. in-chief is ready to serve another term. Bang stated that Yokoyama explained that this was practically realized in no one would be able to compete with the current edi- the last OGM in August because member societies with tor in chief ’s dedication, passion, and energy. Yokoyama unpaid fees did not attend the OGM. Nguyen Quang acknowledged APCTP for continued support to AB. The Liem requested to correct the record to reflect that the appointment of Long to continue as the next editor in Vietnam Physical Society paid for their 2020 membership chief of AB was endorsed by the council. fee. Yokoyama added that AAPPS endorsed the Interna- (6) Gui-Lu Long, the editor in chief of AB reported on tional Symposium on Trans-scale Quantum Science the current status of AB. As of October 2022, 35 articles held at The University of Tokyo, Japan. At the sympo - were published this year, including five articles in the sium, Yokoyama gave a closing remark and introduced News and Views section. The article with the highest cita - activities of AAPPS as well as AB. He found that the main tions was published in 2008, titled “Spin-transfer torque organizer of the symposium already contributed to AB, MRAM (STT-MRAM): Challenges and Prospects” by indicating the increasing reputation of the journal. Prof. Yiming Huai. Other articles in early AB issues have (7) Yokoyama explained that he received an email generally low citations. The role of AB at the earliest stage from Prof. Youngah Park, who served as the chair of the AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 7 of 12 Women-in-Physics Working Group (AAPPS-WIP) for be approved at an OGM, and the next one will be held 16  years. They had a working group meeting on August in 2025; the issue will be transferred to the next council. 23, 2022. The next chair will be Prof. Mihoko Nojiri from Using Grammarly and having advice from native English the Institute of Particle and Nuclear Physics, KEK, Japan, speakers from the next council are suggested. and Prof. Setsuko Tajima, the current president of JPS, (10) Bang stated that there is no recent update on the will serve as the vice chair. This means that the Japanese status of APCTP. Yokoyama informed that Bang will con- community will be taking a leading role in AAPPS-WIP. tinue to be the president of APCTP for the next 3 years. Yokoyama suggested endorsing the decision. He also Yokoyama finally stated that this meeting is the last explained that the next chair requested AAPPS to desig- meeting of this council and expressed his gratitude to nate one of the AAPPS council members to serve as the members for their support through the past 3 years of his liaison to AAPPS-WIP. This matter will be one of the first term. Accordingly, each participant made a short farewell items on the agenda of the new council that is starting speech. The President-elect Choi informed that the first next year. meeting of the new council will be held online in January (8) Yokoyama stated that the pilot program of a joint or February, and the second one is scheduled in spring as award of member societies has started with the Physi- an in-person meeting in Seoul. Ruiqin Zhang reminded cal Society located in Taipei, as a presentation award. that Hong Kong is still available to host a council meeting So far, the first award, which included commemorative in the future. gift, was given to three recipients. Establishing such an Yokoyama closed the meeting. award to further promote cooperation between AAPPS and member societies as an early-career award has 3 2022 Nishina Memorial Prize by Nishina been discussed and approved in previous council meet- Memorial Foundation ings. On behalf of Mio Murao, Yokoyama explained and presented the scope and regulations of the AAPPS-JPS Award, which is becoming the second case of the joint award. The scope of the AAPPS-JPS Award is quite dif - ferent from that of the Physical Society located in Tai- pei. Namely, the candidates for the award will be those who were nominated by the divisions of JPS to the CN Yang Award but were not selected as finalists. Up to five winners will be selected by the AAPPS committee inside JPS among candidates who conducted high-quality and impressive research. Xiang wondered about the restriction on age. Yokoy- ama answered that the qualifications are the same as for the CN Yang Award. Bang expressed his slight worry Dr. Eiji Saitoh Professor, Graduate School of Engineering, University of Tokyo that this new joint award might provide an impression of a kind of remedy for secondary prestige. Although there are both good and worrying aspects, he appre- 3.1 Pioneering contribution to the physics of spin current ciated such efforts by JPS. Xiang considers that the The charge of an electron and its flow, the electric cur - AAPPS-JPS Award could be decoupled from the CN rent, have always been the main physical quantities of Yang Award, though the decision should be made by interest in electronics. The angular momentum, or the JPS. Yokoyama commented that they will try and amend spin, is another fundamental physical quantity of an it if necessary. electron that generates magnetic moment through its Yokoyama proposed to proceed with establishing the polarization and plays an important role in the physics AAPPS-JPS Award, which was seconded by the council. of magnetism and related engineering. Spintronics has Kao informed that the Physical Society located in Tai- emerged as a research field that seeks to discover novel pei intends to continue the joint award and that the next physical phenomena and functionalities through the con- annual meeting will take place in January 2023. trol of spins, within which the flow of spins, or the spin (9) Naka explained that as reported at the last OGM in current, has attracted particular interest. August, some typos in the constitution and bylaws were The spins of conduction electrons in a conductor usu - corrected. She suggested sharing some additional typos ally point either upward or downward in a 50–50 ratio, and possible inconsistencies (highlighted in orange and and thus, the spin transfer associated with the flow of blue in circulated pdf files). As any amendments should electrons is averaged out to zero. The balance between AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 8 of 12 the up- and down-spin flows can be changed to yield a that they injected a spin current into a YIG thin film by net spin current, e.g., by the flow of spin-polarized elec - using the spin Hall effect in a Pt electrode and observed trons in magnetic materials and by the “spin Hall effect,” the propagation of the spin current using the inverse in which, due to spin–orbit interaction in the material, spin Hall effect in another Pt electrode [13]. This also electrons are subject to a force perpendicular to the cur- revealed that angular momentum is transferred between rent’s direction depending on their spin orientations. conduction electrons in the metal electrodes and spin However, a direct method for measuring the spin current excitations in the insulator through the exchange inter- with an external probe was elusive, and experiments were action at the interface. Dr. Saitoh et al. also observed the limited to indirect estimation, e.g., through the obser- spin Seebeck effect in YIG-related oxides [14], pioneer - vation of “spin accumulation” generated at the sample’s ing research on thermoelectric devices using insulating edge by the spin current. materials. In addition, they experimentally demonstrated Dr. Saitoh discovered the “inverse spin Hall effect” in that spin currents are carried not only by magnons in fer- 2006 as a scheme for the direct measurement of spin cur- romagnets but also by various elementary excitations in rent [11]. He used a bilayer metal film of platinum (Pt) and solids, such as magnons in antiferromagnets, spinons in ferromagnetic alloy, permalloy (Ni Fe ). When spin exci- quantum spin liquids [15], magnons in nuclear spin wave 81 19 tations were generated in the permalloy layer through fer- modes [16], and magnetic polarons, coupled excitations romagnetic resonance and injected into the Pt probe layer of magnons and phonons. These achievements revealed through the interface, the spin current was converted into the broad potential of spin current as a probe for the electric current due to the strong spin–orbit interaction study of the physical properties of materials. in Pt, and a voltage signal was detected between the two ends of the Pt layer along the direction perpendicular to the magnetic field. This enabled the direct measurement of the spin current for the first time and led to the sub - stantial development of related research. Since then, Dr. Saitoh and his colleagues have discov- ered various physical phenomena involving spin currents by using this spin-current detection technique men- tioned above. A major achievement among them is the “spin Seebeck effect,” in which a spin current is generated by a temperature gradient applied to a magnetic material and is injected into a probe electrode, e.g., made from Pt, to produce a voltage through the inverse spin Hall effect [12]. In conventional thermoelectric devices based on the Seebeck effect, two different conductors are combined in parallel under a thermal gradient, and the voltage Dr. Eiichiro Komatsu Director, Max Planck Institute for Astrophysics is generated from the difference in the density of states and scattering properties of the conduction carriers in each conductor. The clever idea that led to the discovery 3.2 Contribution to the standard cosmology based of the spin Seebeck effect was to utilize the difference in on cosmic microwave background the behavior of the two spin states of electrons in a single As a theory that explains the global homogeneity and magnetic material. isotropy of the universe, inflationary cosmology, which Dr. Saitoh and his collaborators then extended the postulates that the universe experienced exponential physics of spin current from conductors to insulators. accelerated expansion long before primordial nucleo- They showed that the spin current, as a flow of angu - synthesis, is a very attractive idea. However, in order to lar momentum in solids, is carried not only by conduc- establish it as the standard cosmology, it is important not tion electrons but also by spin excitations in insulators, only to explain such qualitative observational facts but a finding that greatly expanded the concept of spintron - also to quantitatively verify its predictions. These include ics. In ferromagnetic insulating oxides such as yttrium that the universe is spatially flat, has an almost scale- iron garnet (YIG), spin waves, which are collective exci- invariant spectrum originating from quantum fluctua - tation modes of ordered spins of localized electrons, or tions, and generates adiabatic curvature fluctuations and magnons as their elementary excitations, propagate over tensor fluctuations (quantum gravitational waves) that long distances without being scattered by conduction approximately follow Gaussian statistics. electrons. In their 2010 paper, Dr. Saitoh et  al. reported AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 9 of 12 Dr. Komatsu, under the advice of Professor Spergel at represents the deviation of the curvature fluctuation Princeton University, focused on the statistical nature of from the scale invariance of the spectrum. Theoretically, fluctuations and developed a methodology to quantitatively the standard single-field slow-roll inflation model pre - evaluate the deviation from the Gaussian distribution using dicts that the spectral exponent is slightly less than 1, and cosmic microwave background radiation. While Gauss- its value is a major clue to identifying the model. Signs of ian distributions can be characterized only by their ampli- a spectral index deviating from 1 began to appear in the tude and variance, non-Gaussian distributions have infinite 5th year of WMAP data but were rejected with a 99.5% possibilities, making it difficult to quantitatively evaluate statistical confidence level in the 7th year of data [20]. deviations from a Gaussian distribution. They proposed to As described above, WMAP played a decisive role in constrain the deviation to a single parameter, the nonlin- establishing today’s standard cosmology, which predicts ear parameter, and to limit it by observations of the cosmic that structure formation occurred in a universe filled microwave background radiation [17]. Dr. Komatsu estab- with cold dark matter and dark energy, with curvature lished a methodology to measure this by using three-point fluctuations that are nearly scale invariant and follow a correlations (bispectrum) of the cosmic microwave back- Gaussian distribution as the initial conditions as pre- ground radiation and applied it to the data observed by the dicted by inflationary cosmology. Dr. Komatsu played a COBE (COsmic Background Explorer) [18]. leading role in the analysis of WMAP data and contrib- He also joined the research team of the Wilkinson uted greatly to the contemporary standard cosmology. Microwave Anisotropy Probe (WMAP), which was in progress at the time, and applied it to the first-year obser - vation data, quantitatively verifying for the first time that 4 Young Scientist Award of the Physical Society the nonlinear parameter has no significant finite value of Japan, 2023 by JPS and the curvature fluctuation is consistent with a Gauss - Every year, the Physical Society of Japan presents its ian distribution. This was the first quantitative verifica - Young Scientist Awards to young researchers to recog- tion of this phenomenon in the world [19]. At the same nize outstanding achievements in their early research time, he also performed a detailed analysis of the spec- careers. This year’s winners were recently decided by the trum of the fluctuations and found the existence of nearly board of directors of the JPS based on the recommenda- scale-invariant adiabatic curvature fluctuations, as pre - tions of the selection committees established in 19 divi- dicted by standard inflationary cosmology. sions of the JPS. The maximum number of winners from WMAP also showed that the spatial curvature of the each division has been determined based on the number universe is below the limit of measurement, verifying of talks given at the Annual Meetings in the past 3 years. that space is flat as predicted by inflationary cosmology. Each winner is to give an award lecture at the next WMAP also measured the amount of cold dark matter Annual Meeting of the JPS, which is scheduled for March and dark energy, which is responsible for accelerating 2023. Here is the list of winners and their research topics. the expansion of the universe, including error estimates, and found that the current universe consists of about 5% baryons, 22% cold dark matter, and 73% dark energy, 4.1 Theoretical particle physics although these values were updated by the subsequent observations of the Planck mission. In addition, the Hub- • Shinichiro Akiyama (Institute for Physics of Intelli- ble parameter, which expresses the rate of expansion of gence, Faculty of Science, The University of Tokyo): the universe, was precisely measured, and it was revealed “Development of the tensor renormalization group for the first time that the universe is 13.7 billion years old. approach for the lattice field theory” These results confirmed the validity of the cold dark mat - • Zixia Wei (Yukawa Institute for Theoretical Physics, ter model with a cosmological term, which was obtained Kyoto University): “Causal structures and nonlocality at the end of the twentieth century based on a variety of in double holography” observations. It can be said that with the achievement of • Masataka Watanabe (Yukawa Institute for Theoreti - WMAP, cosmology became a precision science. In the cal Physics, Kyoto University): “Development of the third year of the WMAP, Dr. Komatsu took charge of large charge expansion” polarization analysis in addition to the responsibilities he had held since the 1st year and in the 5th year, became responsible for the entire analysis. 4.2 Experimental particle physics During this period, the system of each cosmological parameter measured gradually improved, and signifi - • Tomoko Ariga (Kyushu University): “First neutrino cant values were measured for the spectral index, which interaction candidates at the LHC” AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 10 of 12 4.6 Beam physics • Takuya Nobe (International Center for Elementary Particle Physics, The University of Tokyo): “Search for charginos and neutralinos in final states with two • Lei Guo (Nagoya University Synchrotron Research boosted hadronically decaying bosons and missing Center): “Photo-cathodes Studies for High Perfor- transverse momentum in pp collisions at √s = 13 TeV mance Electron Linear Accelerator” with the ATLAS detector” • Katsuhiro Moriya (Japan Atomic Energy Agency, • Yuto Minami (Research Center for Nuclear Physics, J-PARC center, Accelerator division): “Studies on Beam Osaka University): “New Extraction of the Cosmic Instability in Circular Accelerators Using a Linear Paul Birefringence from the Planck 2018 Polarization Data” Trap” 4.3 Theoretical nuclear physics 4.7 Atomic and Molecular physics, quantum Electronics, and radiation • Yuki Kamiya (Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Phys - • Yuki Takeuchi (NTT Communication Science Labo- ics, Universität Bonn): “K^-p correlation function ratories, NTT Corporation): “Quantum supremacy from high-energy nuclear collisions and chiral SU(3) of measurement-based quantum computation and its dynamics verification” • Kazuki Yoshida (Advanced Science Research Center, • Hiroyuki Tajima (Graduate School of Science, The Japan Atomic Energy Agency): “Alpha clustering in University of Tokyo): “Theoretical study of strongly- atomic nuclei probed by alpha knockout reactions” interacting multi-component Fermi gases” • Ernst David Herbschleb (Institute for Chemical Research, Kyoto University): “Study of coherence 4.4 Experimen tal nuclear physics in solid materials and its exploitation for quantum sensing” • Satoshi Adachi (Cyclotron and Radioisotope Center (CYRIC), Tohoku University): “Search for the α con- densed state in 20Ne and systematic study of inelastic 4.8 Plasma α scattering” • Yuki Kubota (RIKEN Cluster for Pioneering Research): • Naoki Kenmochi (National Institute for Fusion Sci- “Surface Localization of the Dineutron in 11Li” ence): “Experimental study of non-local transport in • Niwase Toshitaka (High-Energy Accelerator Research magnetically confined plasmas” Organization (KEK)): “First direct mass measurement • Kazuki Matsuo (EX-Fusion Inc.): “Experimental of superheavy nuclide” studies on electron thermal energy transport in mag- netized high energy density plasma for fast ignition inertial confinement fusion” 4.5 C osmic ray and astrophysics • Ken Ohashi (Graduate School of Science, Nagoya University): “Effects of diffractive dissociation on 4.9 Magnetism ultra-high energy cosmic rays and measurements of diffractive dissociation using ATLAS and LHCf • Yutaka Akagi (Department of Physics, Graduate detectors” School of Science, The University of Tokyo): “Theo - • Kawaguchi Kyohei (Institute for Cosmic Ray Research, retical studies on topological magnetism and its sta- University of Tokyo): “Theoretical studies on electro - bilization mechanism/emergent phenomena” magnetic radiation from binary neutron star mergers” • Ishikawa Hajime (The Institute for Solid State Phys - • Hiromasa Suzuki (Department of Physics, Faculty of ics, The University of Tokyo): “Development of novel Science and Engineering, Konan University): “Study phases of quantum magnets via ligand field control” of time evolution of the efficiency of particle acceler - • Toshihiro Nomura (The Institute for Solid State ation on supernova remnants with gamma-rays and Physics, The University of Tokyo): “Ultrahigh-mag - thermal X-rays” netic-field study on oxygen” AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 11 of 12 4.10 Semiconductors, mesoscopic systems, and quantum by Spin and Orbital Degrees of Freedom in Strongly transport Correlated Electron System” • Hisashi Inoue (National Institute of Advanced Indus- • Nobuyuki Okuma (Yukawa Institute for Theoretical trial Science and Technology, Research Institute for Physics, Kyoto University): “Elucidation of topological Advanced Electronics and Photonics, Correlated origin of non-Hermitian skin effects and its extension” Electronics Group): “Synthesis and characterization • Yuya Shimazaki (RIKEN Center for Emergent Matter of thin film magnetic topological materials” Science): “Exploration of physical properties in elec- • Yusei Shimizu (International Research Center for trically controlled two-dimensional semiconductor Nuclear Materials Science, Institute for Materials heterostructures” Research, Tohoku University): “Study on supercon- ducting symmetry, magnetic properties, and non- Fermi-liquid metallic state of uranium heavy-fermion 4.11 Optical properties of condensed matter superconductors” • Hakuto Suzuki (Frontier Research Institute for Inter- disciplinary Sciences, Tohoku University): “Resonant • Yuta Murakami (RIKEN Center for Emergent Matter inelastic x-ray scattering study of elementary excita- Science): “Theoretical exploration of high harmonic tions in strongly correlated materials” generation in strongly correlated systems” • Naotaka Yoshikawa (Department of Physics, Gradu- ate School of Science, The University of Tokyo): “Investigation of light-driven electron systems by 4.15 Surfaces and interfaces and crystal growth using intense mid-infrared and terahertz pulses” • Kazuki Sumida (Japan Atomic Energy Agency): “Electronic structure of chalcogenide compounds 4.12 Metal physics (liquid metals, quasicrystals), studied by time-resolved photoemission spectros- low‑temperature physics (ultralow temperatures, copy and magnetic circular dichroism”. superconductivity, density waves) • Kotaro Takeyasu (Faculty of Pure and Applied Sci- ences, University of Tsukuba): “Studies on flow and • Takanobu Hiroto (Materials Analysis Station, National controlling factor of energies in surface reactions”. Institute for Materials Science (NIMS)): “Discovery of ferromagnetic long-range order and non-coplanar spin order in quasicrystal approximants” • Takahiko Makiuchi (Department of Applied Phys- 4.16 Dielectrics, ferroelectricity, lattice defects ics, School of Engineering, The University of Tokyo): and nanostructures, phononic properties, and X‑ray “Study of elastic anomaly in absorbed molecular films and particle beams as a probe of quantum phase transition” • Izumi Umegaki (High-Energy Accelerator Research Organization): “Establishment of techniques using 4.13 Molecular solids muon beam to detect Li diffusion and metallic Li deposition in a Li-ion battery” • Mari Einaga (KYOKUGEN, Graduate School of Engi- • Shota Ono (Department of Electrical, Electronic and neering Science, Osaka University): “Experimental Computer Engineering, Gifu University): “Dynamical Study of Sulfur Hydride Exhibiting Superconductiv- stability of two- and three-dimensional metallic sys- ity above 200 Kelvin” tems from first-principle calculations” • Daichi Kozawa (RIKEN): “Study of exciton photo- physics in low-dimensional nanomaterials” 4.17 Fundamental theory of condensed matter physics, statistical mechanics, fluid dynamics, applied mathematics, and socio‑ and econophysics 4.14 Strongly correlated electron systems • Norihiro Oyama (TOYOTA CENTRAL R&D LABS): • Takuya Aoyama (Department of Physics, Gradu- “Unraveling the origin of universal properties of ate School of Science, Tohoku University): “Study amorphous solids under shear” on Spatial Inversion Symmetry Breaking Induced AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 12 of 12 8. A. Aspect, J. Dalibard, G. Roger, Experimental test of Bell’s inequalities • Ryo Nagai (Department of Physics, The University using time-varying analyzers. Phys. Rev. Lett. 49, 1804–1807 (1982) of Tokyo): “Development of machine-learning-based 9. G. Weihs, T. Jennewein, C. Simon, H. Weinfurter, A. Zeilinger, Violation of exchange correlation functional” Bell’s inequality under strict Einstein locality conditions. Phys. Rev. Lett. 81, 5039–5043 (1998) • Ryo Hanai (Asia Pacific Center for Theoretical Phys - 10. The BIG Bell Test Collaboration, Challenging local realism with human ics): “Study of non-reciprocal phase transitions in choices. Nature 557, 212–216 (2018) non-equilibrium systems” 11. E. Saitoh, M. Ueda, H. Miyajima, G. Tatara, Conversion of spin current into charge current at room temperature: inverse spin-Hall effect. Appl. Phys. • Vu Van Tan (Faculty of Science and Technology, Keio Lett. 88, 182509 (2006) University): “Theoretical studies on the irreversibility 12. K. Uchida, S. Takahashi, K. Harii, J. Ieda, W. Koshibae, K. Ando, S. Maekawa, in non-equilibrium thermodynamics” E. Saitoh, Observation of the spin Seebeck effect. Nature 455, 778 (2008) 13. Y. Kajiwara, K. Harii, S. Takahashi, J. Ohe, K. Uchida, M. Mizuguchi, H. Umezawa, H. Kawai, K. Ando, K. Takanashi, S. Maekawa, E. Saitoh, Trans- mission of electrical signals by spin-wave interconversion in a magnetic 4.18 Soft matter physics, chemical physics, and biophysics insulator. Nature 464, 262 (2010) 14. K. Uchida, J. Xiao, H. Adachi, J. Ohe, S. Takahashi, J. Ieda, T. Ota, Y. Kajiwara, H. Umezawa, H. Kawai, G.E.W. Bauer, S. Maekawa, E. Saitoh, Spin Seebeck • Harukuni Ikeda (Faculty of Science, Gakushuin Uni- insulator. Nat. Mater. 9, 894 (2010) versity): “Numerical and theoretical study of glass 15. D. Hirobe, M. Sato, T. Kawamata, Y. Shiomi, K. Uchida, R. Iguchi, Y. Koike, S. Maekawa, E. Saitoh, One-dimensional spinon spin currents. Nat. Phys. 13, and jamming transition” 30 (2017) • Yuki Uematsu (Faculty of Computer Science and Sys- 16. Y. Shiomi, J. Lustikova, S. Watanabe, D. Hirobe, S. Takahashi, E. Saitoh, Spin tems Engineering, Kyushu Institute of Technology): pumping from nuclear spin waves. Nat. Phys. 15, 22 (2019) 17. E. Komatsu, D.N. Spergel, Acoustic signatures in the primary microwave “Chemical physics and hydrodynamics of solution background bispectrum. Physical Review D 63, 063002 (2001) interfaces” 18. E. Komatsu, B.D. Wandelt, D.N. Spergel, A.J. Banday, K.M. Górski, Measure- • Naoyuki Sakumichi (Department of Bioengineer- ment of the cosmic microwave background bispectrum on the COBE DMR sky maps. Astrophys. J. 566, 19 (2002) ing, School of Engineering, The University of Tokyo): 19. E. Komatsu et al., First year Wilkinson Microwave Anisotropy Probe “Discovery and elucidation of fundamental physical ( WMAP) observations: tests of Gaussianity. Astrophysical Journal Supple- laws of rubbers and gels” ment Series 148, 119 (2003) 20. E. Komatsu et al., Seven year Wilkinson Microwave Anisotropy Probe ( WMAP) observations: cosmological interpretation. Astrophysical Journal Supplement Series 192, 18 (2011) Author’s contributions The author read and approved the final manuscript. Data Availability Not applicable. Declarations Competing interests The authors declare that they have no competing interests. References 1. A. Einstein, B. Podolsky, N. Rosen, Can quantum-mechanical description of physical reality be considered complete? Phys. Rev. 47, 777–780 (1935) 2. D. Bohm, A suggested interpretation of the quantum theory in terms of “hidden” variables. I. Phys. Rev. 85, 166–179 (1952) 3. J.S. Bell, On the Einstein Podolsky Rosen paradox. Physics Physique Fizika. 1, 195–200 (1964) 4. J.F. Clauser, M.A. Horne, A. Shimony, R.A. Holt, Proposed experiment to test local hidden-variable theories. Phys. Rev. Lett. 23, 880–884 (1969) 5. S.J. Freedman, J.F. Clauser, Experimental test of local hidden-variable theories. Phys. Rev. Lett. 28, 938–941 (1972) 6. A. Aspect, P. Grangier, G. Roger, Experimental tests of realistic local theo- ries via Bell’s theorem. Phys. Rev. Lett. 47, 460–463 (1981) 7. A. Aspect, P. Grangier, G. Roger, Experimental realization of Einstein- Podolsky-Rosen-Bohm Gedankenexperiment: a new violation of Bell’s inequalities. Phys. Rev. Lett. 49, 91–94 (1982) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png AAPPS Bulletin Springer Journals

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AAPPS Bulletin (2023) 33:6 AAPPS Bulletin AAPPS Bulletin https://doi.org/10.1007/s43673-023-00075-6 Open Access NE W S AND VIE W S 2022 Nobel Prize in Physics; 53rd AAPPS Council Meeting; 2022 Nishina Memorial Award; 2023 JPS Award AAPPS Bulletin Prize in physics? We try to provide some interpretations 1 2022 Nobel Prize in physics: Bell inequalities of these results. and quantum entanglement by Shang‑Shu Li and Heng Fan 1.2 Quantum entanglement and EPR paradox 1.1 Background It all starts with the mysterious quantum entanglement. Three physicists, Alain Aspect, John F. Clauser, and In 1935, Schrödinger found that under the framework Anton Zeilinger, are awarded the Nobel Prize in physics of quantum mechanics, there would be such a quantum in 2022 for “Experiments with entangled photons, estab- state that the wave functions of two particles could not be lishing the violation of Bell Inequalities and pioneering written as the direct product of the wave functions of sin- quantum information science.” This will undoubtedly add gle particles. Namely, the wave function of two particles impetus to the development of new quantum technol- cannot be separated, and we could only use the whole ogy. Anders lrback, Chairman of the Nobel Committee wave function to describe the two-particle state. This for Physics, pointed out that “The laureates’ work with property seems not to be strange. However, when tak- entangled states is of great importance, even beyond ing account of the quantum mechanics statements about the fundamental questions about the interpretation of measurement and spatial locality, it would lead to the quantum mechanics.” It can be understood that the basic EPR (Albert Einstein, Boris Podolsky, and Nathan Rosen) mechanism and principles of quantum computing and paradox [1] that confuses a lot of people. Consider that quantum information processing are based directly on we can prepare a special entangled state, in which each this year’s Nobel Prize work. particle can be measured to two states: “ + ” and “ − .” In recent years, quantum technology has become According to theory that wave function collapses, in such one of the commanding heights of scientific and tech - an EPR state, when we find the first particle as “ + ” in nological competition. A lot of countries around the measurement, the second particle must be measured as world have invested huge resources in quantum com- “ − ” and vice versa. Note, however, that the collapse of puting, quantum metrology, quantum communication, the wave function in quantum mechanics is instantane- and other quantum technological areas. On the other ous. Even if we separate the two particles sufficiently far hand, quantum mechanics has always been of interests away, the measurement of one particle can also immedi- for public. People usually use quantum mechanics con- ately determine the result of other. It is as if there exists cepts such as “quantum entanglement” and “Schröding- an interaction with speed exceeding the speed of light er’s cat” to describe some daily phenomena in Internet. (action at a distance). This result has been absurd to most So, what is the meaning of quantum entanglement, and people, even Einstein and the co-authors, hence named why did the experiments on Bell’s inequality win Nobel “EPR paradox.” Einstein believed that the world is local or realistic or both, where “local” means that no influence *Correspondence:Association of Asia Pacif, ic Physical Societies, Pohang, can be generated beyond the speed of light, while reality South Korea describes the objective existence of a physical element, © The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/. AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 2 of 12 and our measurements are all derived from this physi- and its value can bex andx . Bob also has two ways of 0 1 cal reality and cannot affect it. But in quantum mechan - measuring y, labeled asy and y . Moreover, it is assumed 0 1 ics, when we make a measurement, the wave function that the measurement can only obtain two outcomes: − 1 will collapse immediately, and the single-shot measure- and + 1. Here, we use a to represent the measured results ment result is random, even still constrained by the cor- of Alice and b for that of Bob. Then after many measure - responding amplitudes. To illustrate this issue, Einstein ments, we can find two facts: (1) when the measurement et al. argued that this result of quantum mechanics is due basis is fixed, the results can present a certain probabil - to that its theory is incomplete. ity distribution. For example, when Alice measures x and This incompleteness is manifested in the hidden varia - Bob measuresy , the values of a and b are always oppo- ble theory proposed by Boehm in 1952 [2]. In this theory, site. When Alice measures x and Bob measuresy , there 1 0 quantum mechanics is still local-realistic, and the EPR is no such correlation, and the probabilities of b to get + 1 paradox is caused by our ignorance of hidden variables. and − 1 are equal. In general cases, we can define the To understand hidden variables, let us take a daily exam- probability distribution of measurement outcomes. Here, ple. Suppose Alice has a pair of shoes, and she will give we use p abxy to represent the joint conditional prob- them to two people who are far apart from each other, ability distribution of outcomes when the measurement Bob and Charlie. Alice has told them there is only one axes are x andy . (2) No matter how far Alice and Bob are pair of shoes. Now, when Bob opens his package, he can from each other, their measurement results always show determine immediately whether Charlie’s shoe is left or correlation, that is as follows: right, which seems to be much like quantum entangle- p abxy ≠ p(ax)p by (1) ment. However, on second thoughts, it is clear that this is not an action at a distance; it is just because Bob knows In the previous section, we mentioned that if the meas- the implicit condition: there is only one pair of shoes. It urement depends on some hidden variable, the results is that implicit condition that makes relevant of Bob and will show a correlation. Let us think about the fact that Charlie’s results. Quantum mechanics in Boehm’s theory we have a variable  in addition. We cannot observe it is more like that the world is still local-realistic, but the for some physical reason, and the value of  can vary in condition such as “one pair of shoes” is not known; per- each measurement. Suppose it also satisfies a probability haps in the EPR case, the separation of the two particles distribution q(λ) . The measurement distribution of Alice has already been determined to be opposite by hidden and Bob is now determined by two variables, which are variables, rather than by the action at a distance in meas- denoted by p(ax, λ) and p by, λ , respectively. What uring. The question then becomes how can we know does the joint probability look like? If we introduce the whether quantum mechanics is described by hidden vari- local condition, the results of Alice and Bob cannot affect ables? That is what Bell’s inequalities solve. each other, and then, the joint probability must be the product form as follows: 1.3 Bell’s inequalities p abxy,  = p(ax, λ)p by, λ The significance of Bell’s inequality is to transfer the (2) problem of whether the world is local-realistic into a Note that under this assumption, due to our ignorance mathematical formula. And, we can test it by designing of the hidden variable  , the observation results average specialized physical experiments. The key to solve the over possible values of  ; the observation results can then problem is that the correlation generated by local hid- be correlated, i.e., as follows: den variable theory has a bound. If this bound is violated, the world is not described by the local hidden variables; p abxy = q()p(ax, )p by, quantum mechanics is complete but nonlocal. The first Bell inequality was proposed by Bell in 1964 [3], and many similar inequalities have been developed in similar ≠ q()p(ax, ) q()p by, � � framework. The Nobel Prize of physics in this year was = p(ax)p by awarded for a series of experiments, such as those veri- fied the violation of Clauser, Home, Shimony, and Holt Equation ( 2 ) is the joint probability distribution (CHSH) inequalities [4]. obtained under the local hidden variable theory. It can CHSH inequality, consider that Alice and Bob are sep- be seen that Alice’s (Bob’s) measurement results only arated by a certain distance, and each has a particle. The depend on the local variable x(y) and the hidden variable state of these two particles may be described by quantum . However, in quantum mechanics, Alice’s measurement mechanics or by hidden variable theory. Suppose Alice results are correlated with that of Bob in some way, so measures the particle in two ways. Let us label it withx , AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 3 of 12 that the joint probability of quantum mechanics may be the correlation function in CHSH inequality can be given beyond the expression ability of formula ( 2 ). Now let us by simple vector multiplication as follows: try to figure out the limitation of the expression under √ √ � � � � � � � � E a , b + E a b + E a , b = 1∕ 2, E a , b =−1∕ 2 localize hidden variable theory, which is Bell’s inequality. 0 0 0 1 1 0 1 1 (5) Let us consider the relationship between the expecta- tions of measurement results, under specified measure - It follows that S = 2 2 > 2 , meaning that quantum ment axes. Define the correlation function as follows: mechanics indeed violate the CHSH inequality. E a , b = p abxy ab x y 1.4 Experimental verification (3) a,b Although Bell inequality is such a simple mathematical formula, experimental verification remains challenging. Furthermore, define the observable S = E a , b + 0 0 First of all, it requires that the entangled states are pre- E a b + E a , b − E a , b . Due to the exist- 0 1 1 0 1 1 pared with high fidelity experimentally and separated at ence of formula ( 2 ), formula ( 3 ) can be written a sufficiently long distance. The experimenter needs to as the sum of product of local expectation value, make sure that the transmission of information below under the distribution of implicit variable, namely or equal the speed of light is excluded when measuring E a , b = ∫ q(λ)E a ;λ E b ;λ . The local expecta - x y x y � � λ the two particles. The second challenge is the ability to tion E a ;λ = ap(a�x, λ) is in the interval [− 1, 1], the measure particles in different arbitrary directions, since same for E b ;λ . only in certain directions quantum mechanics can vio- Now, we have the following: S = dq(λ) E a ;λ E b ;λ + E b ;λ + E a ;λ E b ;λ − E b ;λ 0 0 1 1 0 1 ≤ dq(λ)E b ;λ + E b ;λ  + E b ;λ − E b ;λ 0 1 0 1 ≤ dq λ 2 ≤ 2 ( ) We then obtain the famous CHSH inequality, late Bell’s inequality. In addition, the particle detection efficiency of the detector will also affect the verification S = E a , b + E a b + E a , b − E a , b ≤ 2 0 0 0 1 1 0 1 1 of Bell inequality. Therefore, historically, the verification (4) of Bell’s inequality has been carried out in the process of It is a variation of the original Bell inequality. In other constantly closing the loopholes. words, under the probability distribution obtained by the In 1972, John F. Clauser and Stuart Freedman per- local hidden variable hypothesis, the value of the correla- formed the first Bell experiment [5]. They used the cas - tion function S must satisfy this inequality. If the actual cade transition of calcium atoms to produce entangled measurement results violate this inequality, it means photon pairs. However, because the photon pair genera- that the real world cannot be described by local hidden tion efficiency is very low, the measurement time reaches variable theory. So, does quantum mechanics violate 200  h, and the distance between the two photons is too this inequality? The answer is yes. For example, we pre - short; there is a loophole of locality. In addition, fixed pare Alice and Bob’s particle pairs into the spin singlets measurement base is also one of the reasons for criticism. ψ ⟩ = 1∕ 2(�01⟩ − �10⟩ , where �0 ⟩ and �1 ⟩ are the In 1981 and 1982, Alain Aspect and his collaborators AB eigenvectors of the Pauli operator σ . For any particle, conducted a series of experiments that improved the we can measure the eigenvalue in its quantized direc- measurement accuracy and reduced the loopholes in the �⃗ tion x ⋅ σ �⃗ in the experiment. Let the measured direc- verification of Bell’s inequality. In the first experiment [6 ], �⃗ tion of Alice be x and Bob’s be y �⃗ . Then, the value of the they used a double laser system to excite calcium atoms, correlation function obtained by quantum mechanics is producing pairs of entangled photons and improving the �⃗ −x ⋅ y �⃗ . Now, we use these results to test the CHSH ine- entanglement source. In the second experiment [7], a two- quality and let Alice’s two measurement directions be channel method was used to improve photon utilization. two orthogonal basis x =  e , x =  e . Bob’s two meas- The measurement accuracy has been greatly improved. 0 1 1 2 urement directions are also orthogonal but have an The third experiment [8 ] is the most important for closing angle with Alice’s. If Bob selects the two directions as the locality loophole. In the experiment, the two entangled √ √ � � � � y =−  e +  e ∕ 2, y = − e +  e ∕ 2 , the value of photons are separated by about 12  m, and this distance 0 1 2 1 1 2 AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 4 of 12 needs 40 ns for the signal to travel at the speed of light. The decode it by measurement (without the help of classical distance between the photons and polarizer is 6 m. When means). Second, since there is no classical communica- performing measurement, polarizer rotates for no more tion between Alice and Bob, the probability distribution than 20 ns. Using acousto-optical devices, photons can be of Alice’s measured results will not change regardless switched to two measurement bases on even shorter time of whether Bob measures or not, namely regardless of scales. The measurement time is much less than the time whether Alice’s particles collapse. Therefore, Bob’s meas - it takes for the signal to travel between two photons at the urement operation will not transmit any information to speed of light, closing the locality loophole. Alice. In quantum mechanics, this is represented by the In 1998, Anton Zeilinger’s team tested the Bell inequal- fact that the density matrix describing Alice’s particles ity under strict local conditions [9], with observers up does not change. So, does quantum entanglement make to 400  m apart, closing the locality loophole completely. any sense? Of course, the violation of Bell’s inequality Subsequently, there have been a lot of experiments on the shows that entanglement is a kind of resource that tran- violation of Bell’s inequality. They are all aimed at closing scends classical one, which indicates that even with infi - the loopholes in the verification of quantum mechanics nite classical resources, we cannot achieve the results of from various aspects, so that we are more and more con- quantum entanglement. fident in using quantum mechanics to describe the world. The research of such problems and all other efforts One interesting experiment is the Big Bell Test [10], which gave birth to the second quantum revolution which aims was designed to eliminate the effect of pseudo-random - at the processing and application of quantum informa- ness on the verification of Bell’s inequality. We know that tion. The first quantum mechanical revolution in history random numbers generated by computers in simulations happens after the establishment of quantum mechanics. or experiments are pseudo-random numbers. As long as In this revolution, various classical applications based on we give a certain seed, then the following series of random quantum principles were developed, such as laser, semi- numbers are determined. This leads to the possibility that conductor, and nuclear energy, which enabled mankind the correlation of experimental results measured in this to quickly step into the information age, while the sec- way may exceed the limit represented by Bell’s inequality. ond quantum mechanical revolution is aimed to directly So how do you get a “true” random number? Big Bell develop the applications of quantum coherence and quan- Test proposes to solve this issue by using human’s free tum entanglement in quantum mechanics. Quantum will to generate random numbers, as long as you believe information technology takes quantum bits as the basic that a person’s will is free and random. Okay, no, we do unit, and the generation, transmission, processing, and not believe it neither, maybe the experimenters have OCD detection of quantum information all follow the principle (obsessive–compulsive disorder) or something related. To of quantum mechanics. In the last decades, the develop- solve this problem, the researchers gathered more than ment of quantum computing theory and applications of 100,000 volunteers around the world and asked them to quantum communication have made us see the potential quickly and randomly press either 0 or 1 button in a game of quantum technology to change the world. On the one of tricks. They then uploaded the choices to the cloud hand, the development of quantum technology is to use and randomly sent them to different experimenters to the principles of quantum mechanics to process, transfer, use as random number generators for their experiments. and calculate quantum information; on the other hand, it Through the free will of a large number of participants, also deepens our understanding of quantum mechanics. the Big Bell experiment closed the free choice loophole in a wider scope, strongly negating the localized hidden vari- 2 53rd AAPPS video council meeting able theory. So far, quantum mechanics has been almost by AAPPS perfectly demonstrated to be complete. The 53rd Council Meeting of the Association of Asia Pacific Physical Societies (AAPPS) was held online from 1.5 The second quantum revolution 4:00 p.m. to 6:00 p.m. (UTC + 9 h) on November 28, 2022, Quantum mechanics has been verified to be correct, via a Zoom session hosted by the Asia Pacific Center for but some problems posed by non-locality need to be Theoretical Physics (APCTP). The participants were explained here. For example, can quantum entangle- Jun’ichi Yokoyama (president), Hyoung Joon Choi (vice ment transmit information faster than light? The answer president), Nobuko Naka (secretary), Gui-Lu Long (for- is no; even though it looks like that the action at a dis- mer president, ex officio member), and council members tance travels faster than light, it does not transmit any Xiu-dong Sun (the Chinese Physical Society, Beijing), information. Take the EPR pair as an example. First, since Tao Xiang (the Chinese Physical Society, Beijing), Ruiqin the collapse of the measurement is random, neither Alice Zhang (the Physical Society of Hong Kong), Rajdeep Singh nor Bob can encode the information into the EPR and Rawat (Institute of Physics Singapore), Fu-Jen Kao (the AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 5 of 12 Physical Society located in Taipei), Meng-Fan Luo (the As a nonprofit society, the budget relies on membership Physical Society located in Taipei), and Nguyen Quang fees, registration fees, publications, and donations, as Liem (Vietnam Physical Society). Present as observers support from the ministry is limited. PSI actively uses were Reza Ejtehadi (the Physics Society of Iran), Yunkyu social media, such as Instagram, Youtube, Telegram, Bang (president of APCTP), Jae-Hyung Jeon (executive and Aparat, in addition to PSI’s own website, to share director of APCTP), and Dayoung Yang (AAPPS liaison recorded meetings and events. and editorial staff member). Treasurer Keun-Young Kim Yokoyama asked about the percentage of female physi- and council members Jodie Bradby (Australian Institute of cists in PSI. Ejtehadi responded that 48% of physics Physics (AIP)), Mio Murao (the Physical Society of Japan students and 20% of faculty members are females. The (JPS)), Akira Yamada (the Japan Society of Applied Phys- graduating female students are now gaining faculty posi- ics (JSAP)), Woo-Sung Jung (the Korean Physical Society tions, and the percentage of female faculty members is (KPS)), and Kurunathan Ratnavelu (Malaysian Institute of expected to rapidly increase in the near future. Hyoung Physics) were absent. Joon Choi queried as to why PSI applied to become an (1) Secretary Naka reported the presence of 11 council associate member rather than a full member. Ejtehadi members out of 17 council members. The quorum was answered that PSI has difficulty transferring money for declared as not fulfilled. President Yokoyama informed the payment of membership because of sanctions. that we will have approval later in writing when necessary. After Ejtehadi left the Zoom room, a discussion was (2) Yokoyama opened the 53rd Council Meeting and made by the council. Yokoyama stated that the Ira- welcomed the participants. The agenda was adopted as nian physics community is large, and they are produc- prepared by the president. ing excellent research outcomes. Therefore, it would be (3) Yokoyama introduced Prof. Reza Ejtehadi, the presi- a good idea for PSI to be, for the moment, an associate dent of the Physics Society of Iran (PSI). Ejtehadi made member. Yunkyu Bang agreed that there is no reason not a brief introduction to the society for application to join to accept. However, Bang expressed his concern about AAPPS as an associate member. PSI is a non-profit and the current political environment. Although AAPPS is non-governmental organization with the aim of estab- independent of any political organization, complete sepa- lishing and strengthening scientific cooperation among ration between politics and science is becoming unclear physics researchers, physics teachers, and students stud- these days. Rajdeep Singh Rawat shared his experience ying physics. PSI is the largest and oldest professional as the president of the International Physics Olympiad and scientific society in Iran. The society was established and the research program for plasma fusion and related in 1932 and formally founded in 1963. Activities ceased energy devices in Singapore. Fu-Jen Kao wondered about after the revolution in 1979 and resumed in 1984. The the rights of associate members. Yokoyama clarified that society presently has 11,933 members, including 2463 an associate member has no voting rights at ordinary full members, 1304 associate members, 8158 student general meetings (OGMs) and cannot send any candidate members, and 10 fellows. to become council members. Kao stated that as an asso- The General Assembly is the highest decision-mak - ciate member makes no effect on decisions by the AAPPS ing body of PSI. The board of directors consist of seven Council, the political considerations should be minimal. members. A president, vice president, and treasurer are Tao Xiang suggested changing the name of “associate elected by the board of directors from among themselves. member” to “observer.” Yokoyama responded that the PSI has many branches in areas including condensed associate member status is defined in the constitution. matter physics; particle and high-energy physics; com- Yokoyama proposed to endorse the application, which putational physics; light, atomic, and molecular phys- was seconded by Long and Xiang. The proposal was ics; statistical physics and complex systems; quantum unanimously agreed upon. information; and women in physics. In PSI, there are (4) Choi reported on APPC15, held in August 2022. committees for conferences and events, publications, He explained the list of committee chairs, 14 subjects, prizes and awards, international affairs, and industrial special sessions, and the number of presentations (963 relations. Annual physics conferences have been held presentations in total, consisting of 768 parallel talks, since 1985. Branch meetings and webinars are regularly 168 posters, 15 plenary talks, and 12 special talks). The organized. PSI publishes the Iranian Journal of Physics number of registrations was slightly over 1000, and there Research and the Journal of Applied Fluid Mechanics, in were a few no-shows in the poster sessions. Presently, 30 addition to books, reports, and proceedings. As outreach manuscripts were submitted for the proceedings. The activities, PIS organizes the Physics Club, which has a manuscripts will be sent to the publisher in January 2023, 23-year history and is held monthly in 11 cities across after review and revision processes. At APPC15, there the country, and publishes online newsletters in Persian. was small input from JSAP regarding the applied physics AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 6 of 12 subjects; how to organize the applied physics session at was to serve the association, and joint publication with the next APPC should be considered. Even though spe- APCPT brought steady growth. Currently, articles are cial sessions were open to the public and two plenary published in three ways; i.e., on the website by Springer talks on Monday were open to all member societies, the Nature, AB’s direct website at www. aapps bulle tin. org, audience was not large. This information might not be and in printed form (6 issues/year). The printed copies directly useful for APPC16, which will be held in a face- are mailed every 2  months to the cooperate members to-face manner. Nevertheless, we should strive to have who have paid for the subscription. The total surplus is bigger audiences at APPCs, and we should consider how US $138, with contributions from four member societies we might open the sessions to a wider community. Choi of AAPPS to AB. The article publication charge (APC) commented that the Division of Plasma Physics organizes has been covered by APCPT last year and this year. online meetings on a large scale, where each speaker can The first article, whose APC will be paid by the author invite a free audience. directly, will appear soon. Yokoyama thanked Choi for all his efforts in making The citations of AB are recently improving, particu - APPC15 a successful meeting. Yokoyama commented larly in the fields of particle physics, nuclear physics, and that the number of submitted manuscripts for the pro- quantum information. An expected impact factor is 6 ceedings is rather small. Choi responded that submission or 7. Among 30 published articles this year with already is optional, and most of the participants would not need 61 citations, 11 are original articles compared to only 2 to provide a contribution as they did not have to travel original articles published in 2021. Therefore, the perfor - internationally. The proceedings will be published in an mance of AB in this respect is excellent. online book dedicated to APPC15. Some of the editors have been refreshed regularly, and (5) On behalf of Treasurer Keun-Young Kim, Yokoy- cooperation with Springer Nature will continue for the ama briefly reported on the financial status of AAPPS. target of 40–100 articles to be published each year until The total balance is US $67,028, in addition to the Leo 2025. Springer Nature decided to apply for indexing in Koguan Foundation’s US $36,500. The account state - SCOPUS next year, but application to the Web of Science ments include interest and the dues that 14 societies has been pending. paid for the 2022 membership. Four societies supported Yokoyama expressed his thanks for Long’s dedica- the AAPPS Bulletin (AB) with contributions of US $5000 tion. He also commented that he agrees with the plan to each. JSAP provided support of US $5000 to AAPPS for enhance the News and Views section. Bang asked about international activities, which was partially used for the the status of the article whose APC will be paid by the meetings in Nepal and Thailand. The contribution of author. Long answered that the manuscript is under revi- APCPT of US $545,360 in total is greatly appreciated and sion after the review, and publication in the December or acknowledged. Yokoyama informed that he sent 1 million February issue is expected. Bang stated that it is good to KRW, which he had received as an honorarium for writ- have this kind of article; however, maintaining the rather ing an article in AB, to the representative of the activi- strict conditions for quality control is also important. ties for physicists in Myanmar by the Division of Nuclear Kao informed about a useful database of top journals in Physics. The donation was appreciated by the representa - the world, https:// exaly. com/ journ al. tive, who is a professor at Gifu University in Japan. Yokoyama explained that according to the discussion Kao commented that any member society that does of the Editorial Board in October, the current editor- not pay membership fees has no right to vote at OGMs. in-chief is ready to serve another term. Bang stated that Yokoyama explained that this was practically realized in no one would be able to compete with the current edi- the last OGM in August because member societies with tor in chief ’s dedication, passion, and energy. Yokoyama unpaid fees did not attend the OGM. Nguyen Quang acknowledged APCTP for continued support to AB. The Liem requested to correct the record to reflect that the appointment of Long to continue as the next editor in Vietnam Physical Society paid for their 2020 membership chief of AB was endorsed by the council. fee. Yokoyama added that AAPPS endorsed the Interna- (6) Gui-Lu Long, the editor in chief of AB reported on tional Symposium on Trans-scale Quantum Science the current status of AB. As of October 2022, 35 articles held at The University of Tokyo, Japan. At the sympo - were published this year, including five articles in the sium, Yokoyama gave a closing remark and introduced News and Views section. The article with the highest cita - activities of AAPPS as well as AB. He found that the main tions was published in 2008, titled “Spin-transfer torque organizer of the symposium already contributed to AB, MRAM (STT-MRAM): Challenges and Prospects” by indicating the increasing reputation of the journal. Prof. Yiming Huai. Other articles in early AB issues have (7) Yokoyama explained that he received an email generally low citations. The role of AB at the earliest stage from Prof. Youngah Park, who served as the chair of the AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 7 of 12 Women-in-Physics Working Group (AAPPS-WIP) for be approved at an OGM, and the next one will be held 16  years. They had a working group meeting on August in 2025; the issue will be transferred to the next council. 23, 2022. The next chair will be Prof. Mihoko Nojiri from Using Grammarly and having advice from native English the Institute of Particle and Nuclear Physics, KEK, Japan, speakers from the next council are suggested. and Prof. Setsuko Tajima, the current president of JPS, (10) Bang stated that there is no recent update on the will serve as the vice chair. This means that the Japanese status of APCTP. Yokoyama informed that Bang will con- community will be taking a leading role in AAPPS-WIP. tinue to be the president of APCTP for the next 3 years. Yokoyama suggested endorsing the decision. He also Yokoyama finally stated that this meeting is the last explained that the next chair requested AAPPS to desig- meeting of this council and expressed his gratitude to nate one of the AAPPS council members to serve as the members for their support through the past 3 years of his liaison to AAPPS-WIP. This matter will be one of the first term. Accordingly, each participant made a short farewell items on the agenda of the new council that is starting speech. The President-elect Choi informed that the first next year. meeting of the new council will be held online in January (8) Yokoyama stated that the pilot program of a joint or February, and the second one is scheduled in spring as award of member societies has started with the Physi- an in-person meeting in Seoul. Ruiqin Zhang reminded cal Society located in Taipei, as a presentation award. that Hong Kong is still available to host a council meeting So far, the first award, which included commemorative in the future. gift, was given to three recipients. Establishing such an Yokoyama closed the meeting. award to further promote cooperation between AAPPS and member societies as an early-career award has 3 2022 Nishina Memorial Prize by Nishina been discussed and approved in previous council meet- Memorial Foundation ings. On behalf of Mio Murao, Yokoyama explained and presented the scope and regulations of the AAPPS-JPS Award, which is becoming the second case of the joint award. The scope of the AAPPS-JPS Award is quite dif - ferent from that of the Physical Society located in Tai- pei. Namely, the candidates for the award will be those who were nominated by the divisions of JPS to the CN Yang Award but were not selected as finalists. Up to five winners will be selected by the AAPPS committee inside JPS among candidates who conducted high-quality and impressive research. Xiang wondered about the restriction on age. Yokoy- ama answered that the qualifications are the same as for the CN Yang Award. Bang expressed his slight worry Dr. Eiji Saitoh Professor, Graduate School of Engineering, University of Tokyo that this new joint award might provide an impression of a kind of remedy for secondary prestige. Although there are both good and worrying aspects, he appre- 3.1 Pioneering contribution to the physics of spin current ciated such efforts by JPS. Xiang considers that the The charge of an electron and its flow, the electric cur - AAPPS-JPS Award could be decoupled from the CN rent, have always been the main physical quantities of Yang Award, though the decision should be made by interest in electronics. The angular momentum, or the JPS. Yokoyama commented that they will try and amend spin, is another fundamental physical quantity of an it if necessary. electron that generates magnetic moment through its Yokoyama proposed to proceed with establishing the polarization and plays an important role in the physics AAPPS-JPS Award, which was seconded by the council. of magnetism and related engineering. Spintronics has Kao informed that the Physical Society located in Tai- emerged as a research field that seeks to discover novel pei intends to continue the joint award and that the next physical phenomena and functionalities through the con- annual meeting will take place in January 2023. trol of spins, within which the flow of spins, or the spin (9) Naka explained that as reported at the last OGM in current, has attracted particular interest. August, some typos in the constitution and bylaws were The spins of conduction electrons in a conductor usu - corrected. She suggested sharing some additional typos ally point either upward or downward in a 50–50 ratio, and possible inconsistencies (highlighted in orange and and thus, the spin transfer associated with the flow of blue in circulated pdf files). As any amendments should electrons is averaged out to zero. The balance between AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 8 of 12 the up- and down-spin flows can be changed to yield a that they injected a spin current into a YIG thin film by net spin current, e.g., by the flow of spin-polarized elec - using the spin Hall effect in a Pt electrode and observed trons in magnetic materials and by the “spin Hall effect,” the propagation of the spin current using the inverse in which, due to spin–orbit interaction in the material, spin Hall effect in another Pt electrode [13]. This also electrons are subject to a force perpendicular to the cur- revealed that angular momentum is transferred between rent’s direction depending on their spin orientations. conduction electrons in the metal electrodes and spin However, a direct method for measuring the spin current excitations in the insulator through the exchange inter- with an external probe was elusive, and experiments were action at the interface. Dr. Saitoh et al. also observed the limited to indirect estimation, e.g., through the obser- spin Seebeck effect in YIG-related oxides [14], pioneer - vation of “spin accumulation” generated at the sample’s ing research on thermoelectric devices using insulating edge by the spin current. materials. In addition, they experimentally demonstrated Dr. Saitoh discovered the “inverse spin Hall effect” in that spin currents are carried not only by magnons in fer- 2006 as a scheme for the direct measurement of spin cur- romagnets but also by various elementary excitations in rent [11]. He used a bilayer metal film of platinum (Pt) and solids, such as magnons in antiferromagnets, spinons in ferromagnetic alloy, permalloy (Ni Fe ). When spin exci- quantum spin liquids [15], magnons in nuclear spin wave 81 19 tations were generated in the permalloy layer through fer- modes [16], and magnetic polarons, coupled excitations romagnetic resonance and injected into the Pt probe layer of magnons and phonons. These achievements revealed through the interface, the spin current was converted into the broad potential of spin current as a probe for the electric current due to the strong spin–orbit interaction study of the physical properties of materials. in Pt, and a voltage signal was detected between the two ends of the Pt layer along the direction perpendicular to the magnetic field. This enabled the direct measurement of the spin current for the first time and led to the sub - stantial development of related research. Since then, Dr. Saitoh and his colleagues have discov- ered various physical phenomena involving spin currents by using this spin-current detection technique men- tioned above. A major achievement among them is the “spin Seebeck effect,” in which a spin current is generated by a temperature gradient applied to a magnetic material and is injected into a probe electrode, e.g., made from Pt, to produce a voltage through the inverse spin Hall effect [12]. In conventional thermoelectric devices based on the Seebeck effect, two different conductors are combined in parallel under a thermal gradient, and the voltage Dr. Eiichiro Komatsu Director, Max Planck Institute for Astrophysics is generated from the difference in the density of states and scattering properties of the conduction carriers in each conductor. The clever idea that led to the discovery 3.2 Contribution to the standard cosmology based of the spin Seebeck effect was to utilize the difference in on cosmic microwave background the behavior of the two spin states of electrons in a single As a theory that explains the global homogeneity and magnetic material. isotropy of the universe, inflationary cosmology, which Dr. Saitoh and his collaborators then extended the postulates that the universe experienced exponential physics of spin current from conductors to insulators. accelerated expansion long before primordial nucleo- They showed that the spin current, as a flow of angu - synthesis, is a very attractive idea. However, in order to lar momentum in solids, is carried not only by conduc- establish it as the standard cosmology, it is important not tion electrons but also by spin excitations in insulators, only to explain such qualitative observational facts but a finding that greatly expanded the concept of spintron - also to quantitatively verify its predictions. These include ics. In ferromagnetic insulating oxides such as yttrium that the universe is spatially flat, has an almost scale- iron garnet (YIG), spin waves, which are collective exci- invariant spectrum originating from quantum fluctua - tation modes of ordered spins of localized electrons, or tions, and generates adiabatic curvature fluctuations and magnons as their elementary excitations, propagate over tensor fluctuations (quantum gravitational waves) that long distances without being scattered by conduction approximately follow Gaussian statistics. electrons. In their 2010 paper, Dr. Saitoh et  al. reported AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 9 of 12 Dr. Komatsu, under the advice of Professor Spergel at represents the deviation of the curvature fluctuation Princeton University, focused on the statistical nature of from the scale invariance of the spectrum. Theoretically, fluctuations and developed a methodology to quantitatively the standard single-field slow-roll inflation model pre - evaluate the deviation from the Gaussian distribution using dicts that the spectral exponent is slightly less than 1, and cosmic microwave background radiation. While Gauss- its value is a major clue to identifying the model. Signs of ian distributions can be characterized only by their ampli- a spectral index deviating from 1 began to appear in the tude and variance, non-Gaussian distributions have infinite 5th year of WMAP data but were rejected with a 99.5% possibilities, making it difficult to quantitatively evaluate statistical confidence level in the 7th year of data [20]. deviations from a Gaussian distribution. They proposed to As described above, WMAP played a decisive role in constrain the deviation to a single parameter, the nonlin- establishing today’s standard cosmology, which predicts ear parameter, and to limit it by observations of the cosmic that structure formation occurred in a universe filled microwave background radiation [17]. Dr. Komatsu estab- with cold dark matter and dark energy, with curvature lished a methodology to measure this by using three-point fluctuations that are nearly scale invariant and follow a correlations (bispectrum) of the cosmic microwave back- Gaussian distribution as the initial conditions as pre- ground radiation and applied it to the data observed by the dicted by inflationary cosmology. Dr. Komatsu played a COBE (COsmic Background Explorer) [18]. leading role in the analysis of WMAP data and contrib- He also joined the research team of the Wilkinson uted greatly to the contemporary standard cosmology. Microwave Anisotropy Probe (WMAP), which was in progress at the time, and applied it to the first-year obser - vation data, quantitatively verifying for the first time that 4 Young Scientist Award of the Physical Society the nonlinear parameter has no significant finite value of Japan, 2023 by JPS and the curvature fluctuation is consistent with a Gauss - Every year, the Physical Society of Japan presents its ian distribution. This was the first quantitative verifica - Young Scientist Awards to young researchers to recog- tion of this phenomenon in the world [19]. At the same nize outstanding achievements in their early research time, he also performed a detailed analysis of the spec- careers. This year’s winners were recently decided by the trum of the fluctuations and found the existence of nearly board of directors of the JPS based on the recommenda- scale-invariant adiabatic curvature fluctuations, as pre - tions of the selection committees established in 19 divi- dicted by standard inflationary cosmology. sions of the JPS. The maximum number of winners from WMAP also showed that the spatial curvature of the each division has been determined based on the number universe is below the limit of measurement, verifying of talks given at the Annual Meetings in the past 3 years. that space is flat as predicted by inflationary cosmology. Each winner is to give an award lecture at the next WMAP also measured the amount of cold dark matter Annual Meeting of the JPS, which is scheduled for March and dark energy, which is responsible for accelerating 2023. Here is the list of winners and their research topics. the expansion of the universe, including error estimates, and found that the current universe consists of about 5% baryons, 22% cold dark matter, and 73% dark energy, 4.1 Theoretical particle physics although these values were updated by the subsequent observations of the Planck mission. In addition, the Hub- • Shinichiro Akiyama (Institute for Physics of Intelli- ble parameter, which expresses the rate of expansion of gence, Faculty of Science, The University of Tokyo): the universe, was precisely measured, and it was revealed “Development of the tensor renormalization group for the first time that the universe is 13.7 billion years old. approach for the lattice field theory” These results confirmed the validity of the cold dark mat - • Zixia Wei (Yukawa Institute for Theoretical Physics, ter model with a cosmological term, which was obtained Kyoto University): “Causal structures and nonlocality at the end of the twentieth century based on a variety of in double holography” observations. It can be said that with the achievement of • Masataka Watanabe (Yukawa Institute for Theoreti - WMAP, cosmology became a precision science. In the cal Physics, Kyoto University): “Development of the third year of the WMAP, Dr. Komatsu took charge of large charge expansion” polarization analysis in addition to the responsibilities he had held since the 1st year and in the 5th year, became responsible for the entire analysis. 4.2 Experimental particle physics During this period, the system of each cosmological parameter measured gradually improved, and signifi - • Tomoko Ariga (Kyushu University): “First neutrino cant values were measured for the spectral index, which interaction candidates at the LHC” AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 10 of 12 4.6 Beam physics • Takuya Nobe (International Center for Elementary Particle Physics, The University of Tokyo): “Search for charginos and neutralinos in final states with two • Lei Guo (Nagoya University Synchrotron Research boosted hadronically decaying bosons and missing Center): “Photo-cathodes Studies for High Perfor- transverse momentum in pp collisions at √s = 13 TeV mance Electron Linear Accelerator” with the ATLAS detector” • Katsuhiro Moriya (Japan Atomic Energy Agency, • Yuto Minami (Research Center for Nuclear Physics, J-PARC center, Accelerator division): “Studies on Beam Osaka University): “New Extraction of the Cosmic Instability in Circular Accelerators Using a Linear Paul Birefringence from the Planck 2018 Polarization Data” Trap” 4.3 Theoretical nuclear physics 4.7 Atomic and Molecular physics, quantum Electronics, and radiation • Yuki Kamiya (Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Phys - • Yuki Takeuchi (NTT Communication Science Labo- ics, Universität Bonn): “K^-p correlation function ratories, NTT Corporation): “Quantum supremacy from high-energy nuclear collisions and chiral SU(3) of measurement-based quantum computation and its dynamics verification” • Kazuki Yoshida (Advanced Science Research Center, • Hiroyuki Tajima (Graduate School of Science, The Japan Atomic Energy Agency): “Alpha clustering in University of Tokyo): “Theoretical study of strongly- atomic nuclei probed by alpha knockout reactions” interacting multi-component Fermi gases” • Ernst David Herbschleb (Institute for Chemical Research, Kyoto University): “Study of coherence 4.4 Experimen tal nuclear physics in solid materials and its exploitation for quantum sensing” • Satoshi Adachi (Cyclotron and Radioisotope Center (CYRIC), Tohoku University): “Search for the α con- densed state in 20Ne and systematic study of inelastic 4.8 Plasma α scattering” • Yuki Kubota (RIKEN Cluster for Pioneering Research): • Naoki Kenmochi (National Institute for Fusion Sci- “Surface Localization of the Dineutron in 11Li” ence): “Experimental study of non-local transport in • Niwase Toshitaka (High-Energy Accelerator Research magnetically confined plasmas” Organization (KEK)): “First direct mass measurement • Kazuki Matsuo (EX-Fusion Inc.): “Experimental of superheavy nuclide” studies on electron thermal energy transport in mag- netized high energy density plasma for fast ignition inertial confinement fusion” 4.5 C osmic ray and astrophysics • Ken Ohashi (Graduate School of Science, Nagoya University): “Effects of diffractive dissociation on 4.9 Magnetism ultra-high energy cosmic rays and measurements of diffractive dissociation using ATLAS and LHCf • Yutaka Akagi (Department of Physics, Graduate detectors” School of Science, The University of Tokyo): “Theo - • Kawaguchi Kyohei (Institute for Cosmic Ray Research, retical studies on topological magnetism and its sta- University of Tokyo): “Theoretical studies on electro - bilization mechanism/emergent phenomena” magnetic radiation from binary neutron star mergers” • Ishikawa Hajime (The Institute for Solid State Phys - • Hiromasa Suzuki (Department of Physics, Faculty of ics, The University of Tokyo): “Development of novel Science and Engineering, Konan University): “Study phases of quantum magnets via ligand field control” of time evolution of the efficiency of particle acceler - • Toshihiro Nomura (The Institute for Solid State ation on supernova remnants with gamma-rays and Physics, The University of Tokyo): “Ultrahigh-mag - thermal X-rays” netic-field study on oxygen” AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 11 of 12 4.10 Semiconductors, mesoscopic systems, and quantum by Spin and Orbital Degrees of Freedom in Strongly transport Correlated Electron System” • Hisashi Inoue (National Institute of Advanced Indus- • Nobuyuki Okuma (Yukawa Institute for Theoretical trial Science and Technology, Research Institute for Physics, Kyoto University): “Elucidation of topological Advanced Electronics and Photonics, Correlated origin of non-Hermitian skin effects and its extension” Electronics Group): “Synthesis and characterization • Yuya Shimazaki (RIKEN Center for Emergent Matter of thin film magnetic topological materials” Science): “Exploration of physical properties in elec- • Yusei Shimizu (International Research Center for trically controlled two-dimensional semiconductor Nuclear Materials Science, Institute for Materials heterostructures” Research, Tohoku University): “Study on supercon- ducting symmetry, magnetic properties, and non- Fermi-liquid metallic state of uranium heavy-fermion 4.11 Optical properties of condensed matter superconductors” • Hakuto Suzuki (Frontier Research Institute for Inter- disciplinary Sciences, Tohoku University): “Resonant • Yuta Murakami (RIKEN Center for Emergent Matter inelastic x-ray scattering study of elementary excita- Science): “Theoretical exploration of high harmonic tions in strongly correlated materials” generation in strongly correlated systems” • Naotaka Yoshikawa (Department of Physics, Gradu- ate School of Science, The University of Tokyo): “Investigation of light-driven electron systems by 4.15 Surfaces and interfaces and crystal growth using intense mid-infrared and terahertz pulses” • Kazuki Sumida (Japan Atomic Energy Agency): “Electronic structure of chalcogenide compounds 4.12 Metal physics (liquid metals, quasicrystals), studied by time-resolved photoemission spectros- low‑temperature physics (ultralow temperatures, copy and magnetic circular dichroism”. superconductivity, density waves) • Kotaro Takeyasu (Faculty of Pure and Applied Sci- ences, University of Tsukuba): “Studies on flow and • Takanobu Hiroto (Materials Analysis Station, National controlling factor of energies in surface reactions”. Institute for Materials Science (NIMS)): “Discovery of ferromagnetic long-range order and non-coplanar spin order in quasicrystal approximants” • Takahiko Makiuchi (Department of Applied Phys- 4.16 Dielectrics, ferroelectricity, lattice defects ics, School of Engineering, The University of Tokyo): and nanostructures, phononic properties, and X‑ray “Study of elastic anomaly in absorbed molecular films and particle beams as a probe of quantum phase transition” • Izumi Umegaki (High-Energy Accelerator Research Organization): “Establishment of techniques using 4.13 Molecular solids muon beam to detect Li diffusion and metallic Li deposition in a Li-ion battery” • Mari Einaga (KYOKUGEN, Graduate School of Engi- • Shota Ono (Department of Electrical, Electronic and neering Science, Osaka University): “Experimental Computer Engineering, Gifu University): “Dynamical Study of Sulfur Hydride Exhibiting Superconductiv- stability of two- and three-dimensional metallic sys- ity above 200 Kelvin” tems from first-principle calculations” • Daichi Kozawa (RIKEN): “Study of exciton photo- physics in low-dimensional nanomaterials” 4.17 Fundamental theory of condensed matter physics, statistical mechanics, fluid dynamics, applied mathematics, and socio‑ and econophysics 4.14 Strongly correlated electron systems • Norihiro Oyama (TOYOTA CENTRAL R&D LABS): • Takuya Aoyama (Department of Physics, Gradu- “Unraveling the origin of universal properties of ate School of Science, Tohoku University): “Study amorphous solids under shear” on Spatial Inversion Symmetry Breaking Induced AAPPS Bulletin AAPPS Bulletin (2023) 33:6 Page 12 of 12 8. A. Aspect, J. Dalibard, G. Roger, Experimental test of Bell’s inequalities • Ryo Nagai (Department of Physics, The University using time-varying analyzers. Phys. Rev. Lett. 49, 1804–1807 (1982) of Tokyo): “Development of machine-learning-based 9. G. Weihs, T. Jennewein, C. Simon, H. Weinfurter, A. Zeilinger, Violation of exchange correlation functional” Bell’s inequality under strict Einstein locality conditions. Phys. Rev. Lett. 81, 5039–5043 (1998) • Ryo Hanai (Asia Pacific Center for Theoretical Phys - 10. The BIG Bell Test Collaboration, Challenging local realism with human ics): “Study of non-reciprocal phase transitions in choices. Nature 557, 212–216 (2018) non-equilibrium systems” 11. E. Saitoh, M. Ueda, H. Miyajima, G. Tatara, Conversion of spin current into charge current at room temperature: inverse spin-Hall effect. Appl. Phys. • Vu Van Tan (Faculty of Science and Technology, Keio Lett. 88, 182509 (2006) University): “Theoretical studies on the irreversibility 12. K. Uchida, S. Takahashi, K. Harii, J. Ieda, W. Koshibae, K. Ando, S. Maekawa, in non-equilibrium thermodynamics” E. Saitoh, Observation of the spin Seebeck effect. Nature 455, 778 (2008) 13. Y. Kajiwara, K. Harii, S. Takahashi, J. Ohe, K. Uchida, M. Mizuguchi, H. Umezawa, H. Kawai, K. Ando, K. Takanashi, S. Maekawa, E. Saitoh, Trans- mission of electrical signals by spin-wave interconversion in a magnetic 4.18 Soft matter physics, chemical physics, and biophysics insulator. Nature 464, 262 (2010) 14. K. Uchida, J. Xiao, H. Adachi, J. Ohe, S. Takahashi, J. Ieda, T. Ota, Y. Kajiwara, H. Umezawa, H. Kawai, G.E.W. Bauer, S. Maekawa, E. Saitoh, Spin Seebeck • Harukuni Ikeda (Faculty of Science, Gakushuin Uni- insulator. Nat. Mater. 9, 894 (2010) versity): “Numerical and theoretical study of glass 15. D. Hirobe, M. Sato, T. Kawamata, Y. Shiomi, K. Uchida, R. Iguchi, Y. Koike, S. Maekawa, E. Saitoh, One-dimensional spinon spin currents. Nat. Phys. 13, and jamming transition” 30 (2017) • Yuki Uematsu (Faculty of Computer Science and Sys- 16. Y. Shiomi, J. Lustikova, S. Watanabe, D. Hirobe, S. Takahashi, E. Saitoh, Spin tems Engineering, Kyushu Institute of Technology): pumping from nuclear spin waves. Nat. Phys. 15, 22 (2019) 17. E. Komatsu, D.N. Spergel, Acoustic signatures in the primary microwave “Chemical physics and hydrodynamics of solution background bispectrum. Physical Review D 63, 063002 (2001) interfaces” 18. E. Komatsu, B.D. Wandelt, D.N. Spergel, A.J. Banday, K.M. Górski, Measure- • Naoyuki Sakumichi (Department of Bioengineer- ment of the cosmic microwave background bispectrum on the COBE DMR sky maps. Astrophys. J. 566, 19 (2002) ing, School of Engineering, The University of Tokyo): 19. E. Komatsu et al., First year Wilkinson Microwave Anisotropy Probe “Discovery and elucidation of fundamental physical ( WMAP) observations: tests of Gaussianity. Astrophysical Journal Supple- laws of rubbers and gels” ment Series 148, 119 (2003) 20. E. Komatsu et al., Seven year Wilkinson Microwave Anisotropy Probe ( WMAP) observations: cosmological interpretation. Astrophysical Journal Supplement Series 192, 18 (2011) Author’s contributions The author read and approved the final manuscript. Data Availability Not applicable. Declarations Competing interests The authors declare that they have no competing interests. References 1. A. Einstein, B. Podolsky, N. Rosen, Can quantum-mechanical description of physical reality be considered complete? Phys. Rev. 47, 777–780 (1935) 2. D. Bohm, A suggested interpretation of the quantum theory in terms of “hidden” variables. I. Phys. Rev. 85, 166–179 (1952) 3. J.S. Bell, On the Einstein Podolsky Rosen paradox. Physics Physique Fizika. 1, 195–200 (1964) 4. J.F. Clauser, M.A. Horne, A. Shimony, R.A. Holt, Proposed experiment to test local hidden-variable theories. Phys. Rev. Lett. 23, 880–884 (1969) 5. S.J. Freedman, J.F. Clauser, Experimental test of local hidden-variable theories. Phys. Rev. Lett. 28, 938–941 (1972) 6. A. Aspect, P. Grangier, G. Roger, Experimental tests of realistic local theo- ries via Bell’s theorem. Phys. Rev. Lett. 47, 460–463 (1981) 7. A. Aspect, P. Grangier, G. Roger, Experimental realization of Einstein- Podolsky-Rosen-Bohm Gedankenexperiment: a new violation of Bell’s inequalities. Phys. Rev. Lett. 49, 91–94 (1982)

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Published: Feb 16, 2023

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