Sinya Aoki, YITP
Conserved charges in gravity and entropy
Online (Zoom), indico page, slides (kek.jp only)
We propose a manifestly covariant definition of a conserved charge in gravity. We first define a charge density from the energy momentum tensor with a Killing vector, if exists in the system, and calculate the energy (and angular momentum) of the black hole by a volume integral. Our definition of energy leads to a correction of the known mass formula of a compact star, which includes the gravitational interaction energy and is shown to be 68% of the leading term in some case. Secondly we propose a new method to define a conserved charge in the absence of Killing vectors, and argue that the conserved charge can be regarded as entropy, by showing the 1st law of thermodynamic for a special case. We apply this new definition to the expanding universe, gravitational plane waves and the black hole. We discuss future directions of our research.
Yu Nakayama, Rikkyo University
[QCD theory Seminar] Anomalous hydrodynamics with dyonic charge
Online (Zoom)
We study anomalous hydrodynamics with a dyonic charge. We show that the local second law of thermodynamics constrains the structure of the anomaly in addition to the structure of the hydrodynamic constitutive equations. In particular, we show that not only the usual E ・ B term but also E^2 ? B^2 term should be present in the anomaly with a specific coefficient for the local entropy production to be positive definite.
Yasunori Lee, University of Tokyo
Revisiting Wess-Zumino-Witten terms
Online (Zoom), indico page, slides (kek.jp only)
We revisit various topological issues concerning 4d Wess-Zumino-Witten terms for SU and SO QCD, from the modern bordism point of view. We explain why the definition of the 4d WZW terms requires the spin structure, and also discuss how the mixed anomaly involving the 1-form symmetry of SO QCD is reproduced in the low-energy sigma model.
長谷川眞理子, 総合研究大学院大学
[KEK連携コロキウム] 少子化はなぜ起こるか 人間行動進化学からのアプローチ
Online (Zoom) external homepage
external homepage
自然人類学は、ヒトという生物の進化を研究する学問である。一方、文化人類学、社会人類学は、ヒトが持っているさまざまな文化や社会のあり方を研究する。両方とも、人間についての研究なのだが、アプローチも考え方もまったく異なる。それに対して、人間行動進化学（または進化心理学）は、ヒトという生物の行動や心理の進化を、文化も含めて分析しようとしている。この分野はまだ新しく、誤解されているところも多いので、本講演ではまず、人間行動進化学とは何か、その考え方の枠組みを述べたい。そして、少子化はなぜ起こるのかという具体的な問題について、人間行動進化学での分析による、私の試論を紹介したい。
Kazuya Mameda, RIKEN
Chiral transport under gravitational field
Online (Zoom), slides (kek.jp only)
The kinetic theory is a fundamental tool to describe transport phenomena, such as that induced by quantum anomaly. In this talk, we explain how the Boltzmann transport theory is modified by quantum corrections. Also we show the field-theoretical derivation of the kinetic theory of chiral fermions in general curved spacetime. Then, we briefly discuss possible applications of the resulting framework to high-energy and condensed matter physics.
Hua Xing Zhu, Zhejiang University
[QCD theory Seminar]Double-slit interference in jet substructure and light-ray OPE
Online (Zoom)
The flow of energy within jets is characterized by correlation functions of energy flow operators, with the three-point correlator, being the first correlator with non-trivial shape dependence, playing a special role in unravelling the dynamics of QCD. In this talk we consider the three-point energy correlator to all orders in the strong coupling constant, in the limit where two of the detectors are squeezed together. We show that by rotating the two squeezed detectors with respect to the third by an angle ¥phi?, a ¥cos (2¥phi)cos(2?) dependence arising from the quantum interference between intermediate virtual gluons with +/-+/? helicity is imprinted on the detector. This can be regarded as a double-slit experiment performed with jet substructure, and it provides a direct probe of the ultimately quantum nature of the substructure of jets, and of transverse spin physics in QCD. To facilitate our all-orders analysis, we adopt the Operator Product Expansion (OPE) for light-ray operators in conformal field theory and develop it in QCD. Our application of the light-ray OPE in real world QCD establishes it as a powerful theoretical tool with broad applications for the study of jet substructure.
Kazunori Kohri, KEK
[EX] Higgs vacuum metastability in primordial inflation
Online (Zoom) https://kds.kek.jp/event/36167/ Current measurements of the Higgs boson mass and top Yukawa coupling suggest that the effective Higgs potential develops an instability below the Planck scale. If the energy scale of inflation in the early Universe is as high as the GUT scale, inflationary quantum fluctuations of the Higgs field can easily destabilize the standard electroweak vacuum. This instability produces dangerous AdS domains which should have swallowed the whole Universe.
Current measurements of the Higgs boson mass and top Yukawa coupling suggest that the effective Higgs potential develops an instability below the Planck scale. If the energy scale of inflation in the early Universe is as high as the GUT scale, inflationary quantum fluctuations of the Higgs field can easily destabilize the standard electroweak vacuum. This instability produces dangerous AdS domains which should have swallowed the whole Universe.
Notice: In the seminar, there will be a mini lecture by Prof. Ryuichiro Kitano (KEK theory center) on the renormalization of the Higgs potential prior to Kohri-san’s talk.
Shi Pu, USTC
[QCD theory Seminar] Spin Hydrodynamics and Symmetric Energy-Momentum Tensors
Online (Zoom)
We discuss a puzzle in relativistic spin hydrodynamics; in the previous formulation the spin source from the antisymmetric part of the canonical energy-momentum tensor (EMT) is crucial. The Belinfante improved EMT is pseudo-gauge transformed from the canonical EMT and is usually a physically sensible choice especially when gauge fields are coupled as in magnetohydrodynamics, but the Belinfante EMT has no antisymmetric part. We find that pseudo-transformed entropy currents are physically inequivalent in nonequilibrium situations. We also identify a current induced by the spin vorticity read from the Belinfante symmetric EMT.
Takuya Okuda, Tokyo University
U(1) spin Chern-Simons theory and Arf invariants in two dimensions
Online (Zoom) https://kds.kek.jp/event/36168/
The level-k U(1) Chern-Simons theory with k odd is an example of spin topological quantum field theory (spin TQFT), i.e., a TQFT whose partition functions and states depend on the spin structure of spacetime. Its dynamics is expected to be captured by the 2d CFT of a free compact boson with a certain radius. Recently it was recognized that an appropriate dependence on the 2d spin structure can be given to the CFT by modifying the theory using the so-called Arf invariant. We demonstrate that one can reorganize the torus partition function of the modified CFT into a sum involving a finite number of conformal blocks. This allows us to reproduce the modular matrices of the spin theory. We use the modular matrices to calculate the partition function of the spin Chern-Simons theory on the lens space, and demonstrate the expected dependence on the 3d spin structure. As an introduction to the topic the talk will include an elementary review of the topological phase of matter.
Arata Yamamoto, Tokyo University
Real-time simulation of Z2 lattice gauge theory on qubits
Online (Zoom), indico page, slides (kek.jp only) In this seminar, I talk about the quantum simulation of Z2 lattice gauge theory in 2+1 dimensions. I discuss the real-time evolution of the system with two static charges, i.e., two Wilson lines.
