Keiichi Maeda, Kyoto University
Constraining progenitors and explosion mechanisms of supernovae through their nucleosynthesis characteristics
Meeting room 3, Kenkyu honkan 1F, slides (kek.jp only)
Supernovae (SNe) are the explosive death of stars, either triggered by gravitational collapse of massive stars (CCSNe; core-collapse SNe) or thermonuclear runway of a white dwarf (SNe Ia). Identifying the natures of their progenitors and explosion mechanisms is one of the central issues in stellar astrophysics and observational transient science. In this talk, I will first introduce basic concepts of the SN explosion nucleosynthesis. Then, a review is given on how different progenitors and explosion mechanisms would manifest themselves in observational properties of SNe. Finally, I will quickly go through some examples of recent progresses in individual topics, where the observational data are used to constraint the natures of the progenitors and explosions through the nucleosynthesis arguments; (1) the white dwarf masses and modes of thermonuclear runaway in SNe Ia, (2) the masses of progenitor stars for different classes of CCSNe, and (3) the standard neutrino-driven explosion models and beyond as confronted by the observations of CCSNe and peculiar outliers (such as those associated with Gamma-Ray Bursts).
Tim Maudlin, New York University
What is Wavefunction Realism?
Seminar room, Kenkyu honkan 3F
In the foundations of physics literature, the question is sometimes raised about whether one should—or even can—be a realist about the wavefunction. This query offers two targets for analysis and explication: “realist” and “wavefunction”. The first term is used in many different ways, as is the second, and to get down to a non-trivial and sensible question one has to specify exactly what one has in mind. I will argue that given the only sensible and non-trivial way to make a clear question here, the indeed one ought to be a “realist” about the “wavefunction”. There never should have been much controversy here, and the recent theorem by Pusey, Barrett and Rudolph settles the issue.
Anupam Mazumdar, University of Groningen
Scale free theory of infinite derivative gravity in the ultraviolet
Seminar room, Kenkyu honkan 3F
I will discuss how infinite derivative theory of gravity can be made ghost free and scale free in the ultraviolet to resolve blackhole and cosmological singularities in 4 spacetime dimensions. I will also discuss the consequences for infinite derivative gravity in 3 spacetime dimensions in AdS.
井元信之, 大阪大学
QND測定・状態の空間発展・量子情報処理
Seminar room, Kenkyu honkan 3F
国立大学法人に移籍する前のNTT基礎研究所のときから表題のような研究ができたのは、光ファイバー通信のイノベーションに繋がるからであった。一方、これらの研究を通じて高エネルギー研究所や天文台の方々との会話もあった。研究のスコープも通信のみならず純学問から量子ゲームまで広がって来た。会話を途切れさせないためにあるいはもっと深めるためにも、プロジェクト研究の報告でなく、素朴な疑問から始めて最後はまだ途中の感がある余韻を残して説明を試みたい。
Sergei V. Ketov, Tokyo Metropolitan University and Kavli IPMU
New supergravity framework and its applications to the early Universe cosmology
Meeting room 1, Kenkyu honkan 1F, slides (kek.jp only)
in the first part of my talk I give a very simple introduction to the Dark Side of the Universe (cosmological inflation, dark energy and dark matter), and then briefly review its possible gravitational origin. In the second part of my talk I introduce the supergravity description of the Dark Universe and describe the new tools in the supergravity model building.
Keisuke Harigaya, Institute for Advanced Study
Higgs parity, strong CP problem and unification
Seminar room, Kenkyu honkan 3F
The quartic coupling of the Standard Model Higgs nearly vanishes at a high energy scale. We show that this is explained by the parity symmetry and its spontaneous break down by the condensation of the parity partner of the Higgs. The parity can solve the strong CP problem. The theory is embedded into SO(10) unification and the precise gauge coupling unification is achieved.
山下雅樹, ICRR
地下から探る宇宙暗黒物質実験
先端計測実験棟の多目的室
暗黒物質は銀河団の運動からF. Zwickyにより80年前からその存在を示唆されてきた。その後、銀河の回転速度、宇宙背景放射などの観測により、その存在は確実視されている。一方、素粒子模型からも期待される暗黒物質であるが、未だにその正体は不明である。宇宙の物質の約80%を担っている暗黒物質は我々の身の周りにも飛来し、1Lに数個程度存在していると考えられ、直接探索ではこの粒子の検出を目指している。本講演では地下実験室における液体キセノンを中心とした暗黒物質直接探索実験を紹介する。
Di-Lun Yang, Yukawa Institute of Theoretical Physics, Kyoto University
Chiral kinetic theory and quantum transport of chiral fluids
Seminar room, Kenkyu honkan 3F, slides (kek.jp only) Recently, the anomalous transport of Weyl fermions such as the renowned chiral magnetic effect stemming from the chiral anomaly has been widely studied in relativistic heavy ion collisions, Weyl semimetals, or even in astrophysics. Although such anomalous transport is in general non-dissipative and independent of couplings in thermal equilibrium, the non-equilibrium (or near-equilibrium) transport of Weyl fermions could be affected by other quantum effects and interactions. The chiral kinetic theory (CKT), which delineates quasi-particle transport with the chiral anomaly, is a useful tool to investigate quantum transport in and out of equilibrium for Weyl-fermion systems at weak coupling. In this talk, I will review the recent development of CKT based on quantum field theories, which manifests Lorentz covariance and consistently incorporates collisions. We then apply the CKT to study second-order quantum transport of chiral fluids near local equilibrium. By using a relaxation-time approximation, novel anomalous Hall currents pertinent to interactions and triggered by electric fields and temperature/chemical-potential gradients are discovered. Moreover, the chiral magnetic/vortical effects receive viscous corrections. In addition, one finds that the CKT yields a non-vanishing antisymmetric component of the canonical energy-momentum tensor in chiral fluids with vorticity, which reveals the spin-orbit interaction responsible for angular-momentum transfer in the presence of an axial chemical potential.
Recently, the anomalous transport of Weyl fermions such as the renowned chiral magnetic effect stemming from the chiral anomaly has been widely studied in relativistic heavy ion collisions, Weyl semimetals, or even in astrophysics. Although such anomalous transport is in general non-dissipative and independent of couplings in thermal equilibrium, the non-equilibrium (or near-equilibrium) transport of Weyl fermions could be affected by other quantum effects and interactions. The chiral kinetic theory (CKT), which delineates quasi-particle transport with the chiral anomaly, is a useful tool to investigate quantum transport in and out of equilibrium for Weyl-fermion systems at weak coupling. In this talk, I will review the recent development of CKT based on quantum field theories, which manifests Lorentz covariance and consistently incorporates collisions. We then apply the CKT to study second-order quantum transport of chiral fluids near local equilibrium. By using a relaxation-time approximation, novel anomalous Hall currents pertinent to interactions and triggered by electric fields and temperature/chemical-potential gradients are discovered. Moreover, the chiral magnetic/vortical effects receive viscous corrections. In addition, one finds that the CKT yields a non-vanishing antisymmetric component of the canonical energy-momentum tensor in chiral fluids with vorticity, which reveals the spin-orbit interaction responsible for angular-momentum transfer in the presence of an axial chemical potential.
References :
Di-Lun Yang, arXiv:1807.02395
Yoshimasa Hidaka, Di-Lun Yang, Phys.Rev. D98 (2018) no.1, 016012, arXiv:1801.08253
Yoshimasa Hidaka, Shi Pu, Di-Lun Yang , Phys. Rev. D 97 (2018) no.1, 016004, arXiv:1710.00278
Yoshimasa Hidaka, Shi Pu, Di-Lun Yang , Phys.Rev. D95 (2017) no.9, 091901, (Rapid Communication), arXiv:1612.04630
永長直人, 理研・東大
[第八回KEK連携コロキウム] Chirality in dynamics
つくばキャンパス4号館1階セミナーホール/東海キャンパス東海1号館115号室 (TV会議中継) When the system lacks both parity and mirror symmetries, it is called “chiral” and can be classified into right-handed and left-handed. Chirality is one of the most fundamental issues in many branches of science [1]. In biology, the chirality of DNA is the same for all the living creatures on earth. In chemistry, to synthesize the molecules of one chirality selectively is an important issue. In physics, the parity violation is a striking feature of weak interaction. Here we focus on the chirality appearing in dynamics. It appears trivial that the flows of particles are different between right and left directions when the system is chiral. However, this is not the case as seen from the simplest problem of a single particle scattering problem by one-dimensional asymmetric potential. Namely, the unitary nature of the quantum mechanical time evolution put the constraint on the S-matrix, and the transmission/reflection probabilities are the same for right and left incident waves. Dissipation breaks the unitary nature of the time evolution, and hence the friction, which brings the classical nature of the dynamics, plays an important role for the directional (nonreciprocal) responses of the system. The time-reversal symmetry of the microscopic Hamiltonian also plays an essential role in the nonreciprocal responses of the system. In this talk, I will discuss that the most fundamental principles in physics manifest themselves in the nonreciprocal responses of chiral systems, i.e., the symmetries, dissipation, quantum-classical crossover/transition, quantal Berry phase and topology, and many-body correlation effects. The concrete examples to discuss include magnetochiral anisotropy of semiconductors [2], Weyl semimetals [3], and superconductors [4], nonlinear spin current generation in Rashba-Dresselhaus systems, and shift currents under photo-excitations [5]. The collaborators of these works are T. Morimoto, K.W. Kim, R. Wakatsuki, K. Hamamoto, M. Ezawa, H. Ishizuka, S. Hoshino, S. Koshikawa, S. Shimizu, Y. Kaneko Y. Saito, T. Ideue, Y. Iwasa, and Y. Tokura.
When the system lacks both parity and mirror symmetries, it is called “chiral” and can be classified into right-handed and left-handed. Chirality is one of the most fundamental issues in many branches of science [1]. In biology, the chirality of DNA is the same for all the living creatures on earth. In chemistry, to synthesize the molecules of one chirality selectively is an important issue. In physics, the parity violation is a striking feature of weak interaction. Here we focus on the chirality appearing in dynamics. It appears trivial that the flows of particles are different between right and left directions when the system is chiral. However, this is not the case as seen from the simplest problem of a single particle scattering problem by one-dimensional asymmetric potential. Namely, the unitary nature of the quantum mechanical time evolution put the constraint on the S-matrix, and the transmission/reflection probabilities are the same for right and left incident waves. Dissipation breaks the unitary nature of the time evolution, and hence the friction, which brings the classical nature of the dynamics, plays an important role for the directional (nonreciprocal) responses of the system. The time-reversal symmetry of the microscopic Hamiltonian also plays an essential role in the nonreciprocal responses of the system. In this talk, I will discuss that the most fundamental principles in physics manifest themselves in the nonreciprocal responses of chiral systems, i.e., the symmetries, dissipation, quantum-classical crossover/transition, quantal Berry phase and topology, and many-body correlation effects. The concrete examples to discuss include magnetochiral anisotropy of semiconductors [2], Weyl semimetals [3], and superconductors [4], nonlinear spin current generation in Rashba-Dresselhaus systems, and shift currents under photo-excitations [5]. The collaborators of these works are T. Morimoto, K.W. Kim, R. Wakatsuki, K. Hamamoto, M. Ezawa, H. Ishizuka, S. Hoshino, S. Koshikawa, S. Shimizu, Y. Kaneko Y. Saito, T. Ideue, Y. Iwasa, and Y. Tokura.
References
[1] M. Gardner, The Ambidextrous Universe. Left, Right and the Fall of Parity, Basic Books Inc. (1964)
[2] T. Ideue et al., Nature Physics 13, 578-583 (2017).
[3] T. Morimoto and N. Nagaosa, Phys. Rev. Lett. 117, 146603 (2016).
[4] R. Wakatsuki et al., Science Advances 3, e1602390 (2017)
[5] T. Morimoto and N. Nagaosa, Science Advances 2, e1501524 (2016).
Tomoaki Ishiyama, Chiba University
Supercomputer simulations of dark matter structure formation in the Universe
Meeting room 1, Kenkyu honkan 1F, slides (kek.jp only)
