Institute Of Theoretical Physics Research Articles

High-Energy-Density Physics and Laser Technologies

This paper is devoted to the jubilee of I.M. Khalatnikov, the founder and the first director of the Landau Institute for Theoretical Physics of the Russian Academy of Sciences. I.M. Khalatnikov organized a first-class institute the studies at which cover a broad spectrum of research directions. The plasma and lasers department of the Institute conducts research on plasma physics problems, laser–matter interaction, questions pertaining to laser applications, and hydrodynamics problems. Much attention is given to solid-state physics with an emphasis on the behavior of matter in extreme conditions under intense laser irradiation. A number of new results are presented: the behavior of metals in two-temperature states (when the temperature of the electron subsystem of a metal is much greater than the temperature of the ion subsystem due to ultrafast laser heating); determining the boundaries of existence of a single-wave propagation mode of elastoplastic shock waves in ductile metal crystals; the formation of a laser torch from target materials and liquids under metal laser ablation of a metal into the surrounding liquid; the physical–mechanical consequences (melting, capillarity, recrystallization) of nonuniform (along the irradiated surface) energy dissipation caused by the interference of plasmon–polariton and laser electromagnetic fields.

Tensions between the early and late Universe

The standard cosmological model successfully describes many observations from widely different epochs of the Universe, from primordial nucleosynthesis to the accelerating expansion of the present day. However, as the basic cosmological parameters of the model are being determined with increasing and unprecedented precision, it is not guaranteed that the same model will fit more precise observations from widely different cosmic epochs. Discrepancies developing between observations at early and late cosmological time may require an expansion of the standard model, and may lead to the discovery of new physics. The workshop "Tensions between the Early and the Late Universe" was held at the Kavli Institute for Theoretical Physics on July 15-17 2019 (More details of the workshop (including on-line presentations) are given at the website: https://www.kitp.ucsb.edu/activities/enervac-c19) to evaluate increasing evidence for these discrepancies, primarily in the value of the Hubble constant as well as ideas recently proposed to explain this tension. Multiple new observational results for the Hubble constant were presented in the time frame of the workshop using different probes: Cepheids, strong lensing time delays, tip of the red giant branch (TRGB), megamasers, Oxygen-rich Miras and surface brightness fluctuations (SBF) resulting in a set of six new ones in the last several months. Here we present the summary plot of the meeting that shows combining any three independent approaches to measure H$_0$ in the late universe yields tension with the early Universe values between 4.0$\sigma$ and 5.8$\sigma$. This shows that the discrepancy does not appear to be dependent on the use of any one method, team, or source. Theoretical ideas to explain the discrepancy focused on new physics in the decade of expansion preceding recombination as the most plausible. This is a brief summary of the workshop.

Strings and qubits

Quantum information and string theory researchers met at the Yukawa Institute for Theoretical Physics in Kyoto, Japan for a 5-weeks long workshop to discuss the fascinating interface between their fields.

International Conference on Computer Simulation in Physics and Beyond

PrefaceComputer simulations are well established third pillar of the modern natural sciences. It is the complement to the experiment and theory, and to the emerging the fourth pillar, the extraction of the new knowledge from the big data sets.This volume collects the referred papers based on plenary, invited, and oral talks, as well on the posters presented at the Third International Conference on Computer Simulations in Physics and beyond (CSP2018), which took place September 24-27, 2018 in Moscow. The Conference continues the tradition started by an inaugural conference in 2015. It took place on the campus of A.N. Tikhonov Moscow Institute of Electronics and Mathematics in Strogino, was jointly organized by the National Research University Higher School of Economics, the Landau Institute for Theoretical Physics and Science Center in Chernogolovka.The Conference is a multidisciplinary meeting, with a focus on computational physics and related subjects. Indeed, methods of computational physics prove useful in a broad spectrum of research in multiple branches of natural sciences, and this volume provides a sample.We hope that this volume will interest readers, and we are already looking forward to the next conference in the series.Moscow, RussiaNovember, 2018CSP2018 Conference Chair and Volume EditorLev Shchur

Quantum Gravity on the Computer: Impressions of a Workshop

Computer simulations allow us to explore non-perturbative phenomena in physics. This has the potential to help us understand quantum gravity. Finding a theory of quantum gravity is a hard problem, but, in the last several decades, many promising and intriguing approaches that utilize or might benefit from using numerical methods were developed. These approaches are based on very different ideas and assumptions, yet they face the common challenge to derive predictions and compare them to data. In March 2018, we held a workshop at the Nordic Institute for Theoretical Physics (NORDITA) in Stockholm gathering experts in many different approaches to quantum gravity for a workshop on “Quantum gravity on the computer”. In this article, we try to encapsulate some of the discussions held and talks given during this workshop and combine them with our own thoughts on why and how numerical approaches will play an important role in pushing quantum gravity forward. The last section of the article is a road map providing an outlook of the field and some intentions and goalposts that were debated in the closing session of the workshop. We hope that it will help to build a strong numerical community reaching beyond single approaches to combine our efforts in the search for quantum gravity.

A.I. Akhiezer Institute of Theoretical Physics

Development Strategy of the Institute of Theoretical Physics Akhiezer (hereinafter - ITF) has also passed the test of time: the institute has managed to keep up-to-date scientific directions and the continuity of the leading scientific schools of the UFTI - KIPT. Of course, there were problems. But a serious international ITF rating helped him to resist in the difficult post-Soviet era, and in modern times. The focus of today's ITF is the development of current and advanced frontiers of modern physical science. But most importantly, all the research departments of the ITF have in their staff talented (and very initiative) young scientists, despite the fact that the past years have not very much favored the influx of young people into science. Moreover, their creative achievements were marked by scientific awards of both domestic and international level. The truth that is professed in the ITF: the main thing is not only to accumulate knowledge and experience, but also to pass them on to a worthy change. The fact that the relations in the team are humanly built friendly and democratically helps very well. And it is already obvious: the ITF has withstood the competition in the post-Soviet space and has accumulated a solid scientific potential. Today, the scientific ideology of the ITF is its traditions.

O.I. Akhiezer Institute of Theoretical Physics

Professor A.I. Akhiezer is an outstanding Soviet theoretical physicist who made an outstanding contribution to the development of science. He is one of the most active in the field of theoretical physics of Soviet scientists. He has done about a hundred papers on various problems of nuclear physics, quantum electrodynamics, and the theory of charged particle accelerators. A number of difficult and ingenious studies, which gave fundamental results, made a significant contribution to the development of these problems and made his name known and authoritative among scientists of the Soviet Union and abroad. Professor A.I. Akhiezer is one of the best Soviet theoretical physicists working in the field of atomic nucleus physics and quantum electrodynamics. He is the author of first-class works on the scattering of γ-quanta by nuclei, on the diffraction scattering of nuclear particles. He established the possibility of a new phenomenon — diffraction splitting of deuterons by nuclei. AI Akhiezer is the author of the pioneering work on the scattering of neutrons in crystals, which have become particularly important in connection with the question of the moderation of neutrons. Of great importance was his first work to determine the critical dimensions of the reactor, taking into account the slowing down of neutrons. Of particular note are the works of Professor A.I. Akhiezer and his school on the theory of linear accelerators of charged particles and the theory of plasma.

Sonic velocity in holographic fluids and its applications**Supported by National Natural Science Foundation of China (NSFC) (11575083, 11565017, 11105004), the Fundamental Research Funds for the Central Universities (NS2015073), Shanghai Key Laboratory of Particle Physics and Cosmology (11DZ2260700), the Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (Y5KF161CJ1). In addition,

Gravity/fluid correspondence acts as an important tool in investigating the strongly correlated fluids. We carefully investigate the holographic fluids at the finite cutoff surface by considering different boundary conditions in the scenario of gravity/fluid correspondence. We find that the sonic velocity of the boundary fluids at the finite cutoff surface is critical in clarifying the superficial similarity between the bulk viscosity and perturbation of the pressure for the holographic fluid, where we set a special boundary condition at the finite cutoff surface to explicitly express this superficial similarity. Moreover, we further take the sonic velocity into account to investigate a case with a more general boundary condition. In this more genaral case, although two parameters in the first order stress tensor of holographic fluid cannot be fixed, one can still extract the information about the transport coefficients by considering the sonic velocity seriously.

Spectroscopic and photometric survey of the northern sky: Towards understanding of the Galactic chemical environment in the Solar vicinity

AbstractHigh-resolution spectra for all bright ( mag) and cooler than F5 spectral class dwarf stars were observed in two fields with radii of 20 degrees (centered at (2000) = 161.03º and (2000) = 86.60º and at (2000) = 265.08º and (2000) = 39.58º) towards the northern ecliptic pole. They coincide with two of the preliminary ESA PLATO fields which also will be targeted by the NASA TESS mission. We use high-resolution spectra obtained with the VUES spectrograph mounted on the 1.65 m telescope at the Moletai Astronomical Observatory of the Institute of Theoretical Physics and Astronomy, Vilnius University. In total we observed 405 stars. Spectroscopic atmospheric parameters and abundances of 23 neutral and ionised atomic species were determined for 261 slowly rotating stars (up to 15 kms-1). 73% of stars were analysed spectroscopically for the first time. We also derived stellar ages and orbital parameters to draw a chemical picture of the Solar vicinity.

Spectroscopy of Dwarf Stars Around the North Celestial Pole**Based on observations collected with the 1.65 m telescope and VUES spectrograph at the Molėtai Astronomical Observatory of Institute of Theoretical Physics and Astronomy, Vilnius University, for the SPFOT survey.

New space missions (e.g., NASA-TESS and ESA-PLATO) will perform an in-depth analysis of bright stars in large fields of the celestial sphere searching for extraterrestrial planets and investigating their host-stars. Asteroseismic observations will search for exoplanet-hosting stars with solar-like oscillations. In order to achieve all the goals, a full characterization of the stellar objects is important. However, accurate atmospheric parameters are available for less than 30% of bright dwarf stars of the solar neighborhood. In this study we observed high-resolution (R = 60,000) spectra for all bright (V < 8 mag) and cooler than F5 spectral class dwarf stars in the northern-most field of the celestial sphere with radius of 20° from the α(2000) = 161.°03 and δ(2000) = 86.°60 that is a center of one of the preliminary ESO-PLATO fields. Spectroscopic atmospheric parameters were determined for 140 slowly rotating stars, for 73% of them for the first time. The majority (83%) of the investigated stars are in the TESS object lists and all of them are in the preliminary PLATO field. Our results have no systematic differences when compared with other recent studies. We have 119 stars in common with the Geneva–Copenhagen Survey, where stellar parameters were determined photometrically, and find a 14 ± 125 K difference in effective temperatures, 0.01 ± 0.16 in log g, and −0.02 ± 0.09 dex in metallicities. Comparing our results for 39 stars with previous high-resolution spectral determinations, we find only a 7 ± 73 K difference in effective temperatures, 0.02 ± 0.09 in log g, and −0.02 ± 0.09 dex in metallicities. We also determined basic kinematic and orbital parameters for this sample of stars. From the kinematical point of view, almost all our stars belong to the thin disk substructure of the Milky Way. The derived galactocentric metallicity gradient is −0.066 ± 0.024 dex kpc−1 (2.5σ significance) and the vertical metallicity gradient is −0.102 ± 0.099 dex kpc−1 (1σ significance) that comply with the latest inside-out thin disk formation models, including those with stellar migration taken into account.

V03-08 THE NEW DEVICE FOR LITHOEXTRACTION DURING CONVENTIONAL PCNL. NO BASKETS, NO GRASPERS

You have accessJournal of UrologyUrolithiasis & Endourology1 Apr 2018V03-08 THE NEW DEVICE FOR LITHOEXTRACTION DURING CONVENTIONAL PCNL. NO BASKETS, NO GRASPERS Stanislav Ali, Nikolay Grigoriev, Housein Ali, Evgenii Bezrukov, Roman Sukhanov, Alim Dymov, and Petr Glybochko Stanislav AliStanislav Ali More articles by this author , Nikolay GrigorievNikolay Grigoriev More articles by this author , Housein AliHousein Ali More articles by this author , Evgenii BezrukovEvgenii Bezrukov More articles by this author , Roman SukhanovRoman Sukhanov More articles by this author , Alim DymovAlim Dymov More articles by this author , and Petr GlybochkoPetr Glybochko More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.833AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Traditional percutaneous nephrolithotomy (PCNL) with pneumatic/laser lithotripsy requires the use of lithoextractors. PCNL is associated with additional economic and time costs. We developed a new device that may offer an alternative to the lithoextractors. METHODS In collaboration with the Institute of Theoretical Physics we invented a new additional Amplatz device for PCNL, that is for the inflow of the irrigational fluid into the cavity of the pelvicalyceal system through the sheath and the outflow through the irrigation channel of the nephroscope. Taking into consideration the change of the core principles of the fluid flow circulation the method was named «The Inversion Technique». 21 patients with a single kidney stone were enrolled in the prospective non-randomized study. For the first group (1st, N=10) an additional devise was used to create the inversion flow of the fluid, while for the second group (2nd, N=11) a conventional PCNL with a traditional fluid supply through the nephroscope was performed. Each surgery was video recorded in order to estimate the exact time required for the change of the instruments used in the 1st group and lithotripsy duration in the 2nd group. In addition, changing of the intrarenal pressure stone-free rate (SFR) and complications were evaluated. RESULTS The stones sizes were 23±3 mm in the 1st and 23.5±2 mm 2nd group, respectively. The average time of procedure was 45±10min in the 1st group and 50±3 min − 2nd group. The median of the overall time of both lithotripsy and lithoextraction was 14±2 min in the first group and 17±3 min in the 2nd group. The required time for the instruments change in the 2nd group was 8±4 min. No complications were noted in the postoperative period. The SFR was 99% in the 1st group and 96% in the 2nd group. The intrarenal pressure of the 1st group did not exceed 10cm H2O, of the 2nd - 55cm H2O. CONCLUSIONS The new approach is safe and enables to reduce the time of lithotripsy in case of the simultaneous lithoextraction. Achievement of the effect even at vertical position, the possibility of the permanent capture of fragments, no proximal migration of the stones and no significant changes of the intrapelvical pressure were observed. The above-mentioned advantages allow to avoid the use of lithoextractors in routine treatment of the stones. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e324 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Stanislav Ali More articles by this author Nikolay Grigoriev More articles by this author Housein Ali More articles by this author Evgenii Bezrukov More articles by this author Roman Sukhanov More articles by this author Alim Dymov More articles by this author Petr Glybochko More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

REFACTORING OF THE OPENVZ DRIVER FOR THE OPENNEBULA CLOUD PLATFORM WITHIN THE JINR CLOUD INFRASTRUCTURE PROJECT

This article explores the possibilities of using OpenVZ virtualization technology in the cloud infrastructure of the Joint Institute for Nuclear Research (JINR), built on the OpenNebula platform. OpenNebula is an open and extensible cloud platform allowing an easy automation of data centers operations. Simplicity of deployment and configuration of virtual machines without the help of specialists is the main advantage of the OpenNebula platform. Also, the main advantages of this cloud platform include the ability to dynamically change the size of the physical infrastructure by adding and removing nodes in real time and splitting the cluster into virtual partitions, which allows us to allocate only the necessary amount of resources for the operation of a certain service. OpenNebula provides a centralized interface for managing all elements of the infrastructure, both virtual and physical, and also has a high degree of utilization of available resources. Initially, OpenNebula does not support the OpenVZ virtualization technology, however its modular architecture allows using third-party drivers, in particular for OpenVZ. To deploy the virtualization technology within OpenNebula, a driver was developed by JINR and the Bogolyubov Institute of Theoretical Physics. The main advantage of OpenVZ virtualization technology is the ability to run multiple isolated copies of the operating system on a single physical server. The authors of this article had to refactor the code of the existing OpenVZ driver for the OpenNebula cloud platform. The work was done using the Ruby software environment. The results obtained are currently used in the JINR cloud infrastructure.

Walter Kohn. 9 March 1923—19 April 2016

Walter Kohn, a giant of theoretical physics, died at his home in Santa Barbara, California, on 19 April 2016, at the age of 93. Walter's life epitomized both the hardships and the wondrous achievements of physicists in the twentieth century. He escaped from Nazi-occupied Austria on one of the last children's rescue trains (the Kindertransport ) and during World War II spent 18 months confined in internment camps in England and Canada. He learned only after the War that both of his parents had perished in Auschwitz. After earning physics degrees at the University of Toronto and at Harvard University, he rapidly emerged as a leader in bringing quantum theory to bear on problems in the electron theory of solids. Walter's devotion to basic scientific principles led to the density functional theory of electrons in solids and in chemical molecules in the 1960s. Thirty years later, once the vast importance of this theory had become clear, he was awarded a Nobel Prize in Chemistry for this discovery. In his later years Walter turned much of his attention to institution building and public affairs. He was the founding director of the Institute for Theoretical Physics at the University of California, Santa Barbara. He was deeply committed to the control of nuclear weapons, the development of renewable clean energy and the free exchange of knowledge among scientists throughout the world.

Explaining DAMPE results by dark matter with hierarchical lepton-specific Yukawa interactions**Supported by National Natural Science Foundation of China (11105124, 11105125, 11375001, 11675147, 11675242), the Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences (Y5KF121CJ1), the Innovation Talent project of Henan Province (15HASTIT017), the Young-Talent Foundation of Zhengzhou University, the CAS Center

We propose to interpret the DAMPE electron excess at 1.5 TeV through scalar or Dirac fermion dark matter (DM) annihilation with doubly charged scalar mediators that have lepton-specific Yukawa couplings. The hierarchy of such lepton-specific Yukawa couplings is generated through the Froggatt-Nielsen mechanism, so that the dark matter annihilation products can be dominantly electrons. Stringent constraints from LEP2 on intermediate vector boson production can be evaded in our scenarios. In the case of scalar DM, we discuss one scenario with DM annihilating directly to leptons and another scenario with DM annihilating to scalar mediators followed by their decays. We also discuss the Breit-Wigner resonant enhancement and the Sommerfeld enhancement in the case where the s-wave annihilation process is small or helicity-suppressed. With both types of enhancement, constraints on the parameters can be relaxed and new ways for model building can be opened in explaining the DAMPE results.

Protection-against-water-attack determined difference between strengths of backbone hydrogen bonds in kinesin’s neck zipper region**Project supported by the National Natural Science Foundation of China (Grant No. 11605038) and the Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (Grant No. Y5KF211CJ1).

Docking of the kinesin’s neck linker (NL) to the motor domain is the key force-generation process of the kinesin. In this process, NL’s β10 portion forms four backbone hydrogen bonds (HBs) with the motor domain. These backbone hydrogen bonds show big differences in their effective strength. The origins of these strength differences are still unclear. Using molecular dynamics method, we investigate the stability of the backbone HBs in explicit water environment. We find that the strength differences of these backbone HBs mainly arise from their relationships with water molecules which are controlled by arranging the surrounding residue sidechains. The arrangement of the residues in the C-terminal part of β10 results in the existence of the water-attack channels around the backbone HBs in this region. Along these channels the water molecules can directly attack the backbone HBs and make these HBs relatively weak. In contrast, the backbone HB at the N-terminus of β10 is protected by the surrounding hydrophobic and hydrophilic residues which cooperate positively with the central backbone HB and make this HB highly strong. The intimate relationship between the effective strength of protein backbone HB and water revealed here should be considered when performing mechanical analysis for protein conformational changes.

Tunnelling Phenomenon near an Apparent Horizon in Two-Dimensional Dilaton Gravity**Supported by the National Natural Science Foundation of China under Grant Nos. 11622543 and 11235010, and by the Open Project Program of Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (No. Y5KF161CJ1)

Based on the definition of the apparent horizon in a general two-dimensional dilaton gravity theory, we analyze the tunnelling phenomenon near the apparent horizon. In this theory the definition of the horizon is very different from those in higher-dimensional gravity theories. By using the Hamilton–Jacobi method, the spectrum of the radiation is obtained and the temperature of the radiation is read out from this spectrum. The temperature is proportional to the surface gravity of the apparent horizon as usual. Besides, in stationary cases we calculate the spectrum by using Parikh and Wilczek’s null geodesic method and the result conforms to that obtained by using the Hamilton–Jacobi method. This is expected since the Hamilton–Jacobi method applies to generic spacetimes, including stationary ones.

Evaluation of Particle Numbers via Two Root Mean Square Radii in a 2-Species Bose–Einstein Condensate**Supported by the National Natural Science Foundation of China under Grant Nos. 11372122, 11274393, 11574404, and 11275279; the Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China; and the National Basic Research Program of China (2013CB933601);

The coupled Gross–Pitaevskii equations for two-species BEC have been solved analytically under the Thomas-Fermi approximation (TFA). Based on the analytical solution, two formulae are derived to relate the particle numbers NA and NB with the root mean square radii of the two kinds of atoms. Only the case that both kinds of atoms have nonzero distribution at the center of an isotropic trap is considered. In this case the TFA has been found to work nicely. Thus, the two formulae are applicable and are useful for the evaluation of NA and NB.

IF-YITP GR+HEP+Cosmo International Symposium VI

PrefacePiero NicoliniE-mail: nicolini@fias.uni-frankfurt.deFrankfurt Institute for Advandced Studies (FIAS), Frankfurt am Main, GermanyandInstitut für Theoretische Physik, Goethe-Universitat Frankfurt am Main, GermanyDouglas SingletonE-mail: dougs@mail.fresnostate.eduDepartment of Physics, California State University Fresno, CA, USAandInstitute of Experimental and Theoretical Physics Al-Farabi KazNU, Almaty, KazakhstanShingo TakeuchiE-mail: shingo.portable@gmail.comThe Institute for Fundamental Study, “The Tah Poe Academia Institute”, Naresuan University, Phitsanulok, ThailandMatthew J. LakeE-mail: matthewj@nu.ac.thThe Institute for Fundamental Study, “The Tah Poe Academia Institute”, Naresuan University, Phitsanulok, ThailandandThailand Center of Excellence in Physics, Ministry of Education, Bangkok, ThailandVladimir DzhunushalievE-mail: v.dzhunushaliev@gmail.comInstitute of Experimental and Theoretical Physics Al-Farabi KazNU, Almaty, KazakhstanIntroductionThe Institute for Fundamental Study (IF) hosted the 6th IF+YITP International Symposium on superstring theory, the quantum theory of fields, gravity, cosmology, and related topics, on August 3rd through 5th, 2016, on the campus of Naresuan University, Thailand. This version of the symposium was co-sponsored by the Yukawa Institute for Theoretical Physics (YITP). These symposia have two principle aims. First, to bring together researchers from Thailand and around the world to discuss new ideas in fundamental physics. Second, these meetings are to support the recently established Institute for Fundamental Study (The Tah Poe Academia Institute) centered in Naresuan University in Phitsanulok, Thailand. The 6th symposium was a great success in terms of these two goals. The meeting had eight invited speakers and over 60 participants from both inside and outside Thailand. A host of new models and theories were presented at this symposium which covered a wide range of theoretical topics from cosmology to quantum field theory to superstring theory. The list of invited speakers and their talk titles is Committees and List of Participants are available in this PDF.AcknowledgmentsThe meeting was co-sponsored by the Asia Pacific Center for Theoretical Physics (APCTP), Pohang, Korea, Naresuan University, Phitsanulok, Thailand and the Yukawa Institute for Theoretical Physics (YITP), Kyoto, Japan. IF thanks the APCTP for providing generous financial support for several of the workshop participants and the YITP for their financial and logistical support for the meeting.

We have confidence to lead gravitational-wave science: an interview with Yueliang Wu

Abstract Yueliang Wu, chief scientist of Taiji Program, is a well-known theoretical physicist and the Vice-President of the University of Chinese Academy of Sciences (UCAS). Taiji Program, initially proposed in 2008, is one of China's ambitious plans to observe gravitational waves. Obtaining his Ph.D. at the Institute of Theoretical Physics (ITP) under the Chinese Academy of Sciences (CAS) in 1987, Wu had been working at Dortmund University and Mainz University in Germany and Carnegie-Mellon University and the Ohio-State University in the USA. In 1996, he joined the ITP and became its director in 2007. He has also served as the Director of the Kavli Institute for Theoretical Physics China at the CAS since 2006. In 2007, he was elected as a CAS member. Wu's research is focused on elementary particle physics, quantum field theory, symmetry principle and cosmophysics. In recent years, he has been proposing a gravitational quantum field theory as a new approach to reconciling the general theory of relativity and quantum mechanics. The most fundamental unanswered question of the general theory of relativity is how general relativity can be reconciled with the laws of quantum physics to produce a complete and self-consistent theory of quantum gravity. To extend the general relativity to realize the reconciliation, Wu suggested a basic gravitational field be needed in the future model. Since 2012, he, together with Wenrui Hu, has been working as Taiji Program's chief scientist and promoting nationwide gravitational-wave research. National Science Review (NSR) spoke with Wu about the future of gravitational-wave research, the development of China's nationwide gravitational-wave studies and particularly the progress of Taiji Program.

Spatial and temporal variations of the fine-structure constant in the Finslerian universe**Supported by Fundamental Research Funds for Central Universities (106112016CDJCR301206), National Natural Science Fund of China (11305181, 11547035, 11603005), and Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (Y5KF181CJ1).

Recent observations show that the electromagnetic fine-structure constant, αe, may vary with space and time. In the framework of Finsler spacetime, we propose here an anisotropic cosmological model, in which both spatial and temporal variations of αe are allowed. Our model naturally leads to the dipole structure of αe, and predicts that the dipole amplitude increases with time. We fit our model to the most up-to-date measurements of αe from the quasar absorption lines. It is found that the dipole direction points towards (l,b) = (330.2°±7.3°,−13.0°±5.6°) in galactic coordinates, and the anisotropic parameter is b0 = (0.47±0.09) × 10−5, which corresponds to a dipole amplitude (7.2±1.4)×10−8 at redshift z = 0.015. This is consistent with the upper limit of the variation of αe measured in the Milky Way. We also fit our model to Union2.1 type Ia supernovae, and find that the preferred direction of Union2.1 is consistent with the dipole direction of αe.