Nazila Mahmoudi, Lyon University
[IPNS Physics and Theory Seminar] The Post-R_K Landscape: B Anomalies and Implications for New Physics
Hybrid On-site: Kenkyu Honkan 1F meeting room1 Online: Zoom
I will discuss the role of inclusive and exclusive b-> c(u) l nu decays in the extractions of $|V_{cb}|$ and $|V_{ub}|$. I will update the precision extractions of the observables associated with a few related exclusive decay modes. Also, I will focus on the possible role of the available data on these decays in constraining the parameters associated with the new interactions beyond the SM.
Kazuya Fujimoto, Titech
Review on applications of nonthermal fixed points to ultracold atoms
Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
Universal dynamics associated with scale-invariant properties has garnered much attention in the field of statistical mechanics for a long time. Thanks to the high controllability of ultracold atom experiments, such universal quantum dynamics has been studied theoretically and experimentally over a decade from the perspective of nonthermal fixed points, which was originally introduced in the context of high-energy physics. In this talk, we will begin with an introduction to ultracold atoms, reviewing applications of nonthermal fixed points to ultracold atoms by showing recent theoretical and experimental achievements.
古林敬顕, 秋田大学
[金茶会] 脱炭素社会に向けたエネルギー需給の現状と将来
東海キャンパスAQBRC2階会議室 リモート会場 ：3号館セミナーホール https://www-conf.kek.jp/kincha/
https://www-conf.kek.jp/kincha/
2050年のカーボンニュートラル社会実現のためには、原子力や再生可能エネルギーの導入促進による化石燃料削減、エネルギー効率の向上による最終エネルギー消費量の削減、森林などによる温室効果ガスの吸収量の増加が重要となる。本講演では、日本のエネルギー需給の現状および再生可能エネルギーやエネルギー需要の偏在性を踏まえて、脱炭素化に向けて導入が求められる技術、インフラ、政策などについて、エネルギーシステムの知見に基づいて説明する。
Björn Garbrecht, Technical University of Munich
CP conservation in the strong interactions
Online (Zoom) There is no empirical evidence for CP conservation in the strong interactions. As there generally is a renormalizable, parity-odd coupling between the field strength and its dual, this requires an explanation from theory.
There is no empirical evidence for CP conservation in the strong interactions. As there generally is a renormalizable, parity-odd coupling between the field strength and its dual, this requires an explanation from theory.
I will therefore first review what interactions are present when constructing an effective theory for hadrons from QCD. But I will also point out, that from such considerations alone, it cannot be decided whether the effective interactions (that, e.g., give mass to eta-prime) are misaligned (CP violation) or aligned (no CP violation) with the quark mass phase.
To see whether or not there is a material effect of the parity-odd operator in QCD requires therefore an understanding of how field configurations from different topological sectors contribute to the path integral or, in canonical quantization, whether topology implies different ground states that are in general not parity eigenstates. To that end, I will review the pertinent homeomorphisms between the SU(2) subgroups of the strong interactions and the boundaries of spacetime or spatial hypersurfaces.
As for the Euclidean path integral approach, I will note that pure gauge configurations on the boundary only follow when the latter is placed at infinity. Picard-Lefschetz theory then implies that steepest-descent integration contours cover all field configurations within a topological sector that one can find in the infinite spacetime volume. Consequently, the limit of infinite spacetime volume must be taken before summing over sectors, and it turns out that parity violation then vanishes. Commuting these limits, as tacitly done in standard approaches, corresponds to a singular deformation of the original Cauchy contour, falsely suggesting parity-violating results.
Regarding canonical quantization, I will note that the usually considered theta-vacua are not properly normalizable, which is at odds with the probability interpretation from the axioms of quantum mechanics. The root of this problem is the summation over gauge-redundant configurations in the orthonormality relations among theta-vacua. Imposing that (in temporal gauge) the wave functionals and Hilbert-space operators are well-defined when the inner product covers each physical field configuration one time and one time only, I recover that the consistent states satisfy Gauß’ law and are moreover eigenstates of parity.
References:
2001.07152 [hep-th]
2403.00747 [hep-th]
2404.16026 [hep-ph]
So Matsuura, Keio University
Phases and Duality in Fundamental Kazakov-Migdal Model on the Graph
Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
In this talk, we will explore the fundamental Kazakov-Migdal (FKM) model on a generic graph, where the partition function is represented by the Ihara zeta function weighted by unitary matrices. The effective action of the FKM model is described by a summation of all Wilson loops on the graph, which can be regarded as an extension of the usual Wilson action in lattice gauge theory. We show that the FKM model on regular graphs exhibits an exact strong/weak coupling duality, reflecting the functional equation of the Ihara zeta function. Although this duality is not precise for irregular graphs, we show that the effective action in the large coupling region can also be represented by a summation of Wilson loops, similar to that in the small coupling region. We also discuss the stability of the model and show that the FKM model becomes unstable in the critical strip of the Ihara zeta function. Interestingly, the FKM model universally exhibits the so-called Gross-Witten-Wadia (GWW) phase transitions. By comparing the FKM model with the GWW model, we estimate the phase structure of the FKM model in both small and large coupling regions, which is validated through numerical simulations. For the benefit of graduate students, we will begin the seminar with an introductory explanation of lattice gauge theory and graph theory, providing a foundation for understanding the subsequent discussion.
梶洋隆, トヨタ自動車株式会社未来創生センター
[金茶会] 未来につながる研究：トヨタ自動車未来創生センターの取組み
４号館セミナーホール リモート会場：東海キャンパスAQBRC2階会議室 https://www-conf.kek.jp/kincha/
https://www-conf.kek.jp/kincha/
未来創生センターは、モビリティ・カンパニーへの変革を目指すトヨタ自動車の先端研究の分野を担う研究センターです。本講演では、未来創生センターの概要とロボティクス、ライフサイエンス、社会インフラ、数理・データサイエンスの四つの分野の研究開発事例、および講演者がこれまで取り組んできたAI研究についてご紹介します。
Soumitra Nandi, IIT Guwahati
Interpretations of the data on b-> c(u) l nu decays: SM and beyond
Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
I will discuss the role of inclusive and exclusive b-> c(u) l nu decays in the extractions of $|V_{cb}|$ and $|V_{ub}|$. Also, I will focus on the possible role of the available data on these decays in constraining the parameters associated the new interactions beyond the SM.
Sotaro Sugishita, YITP
Subregion Complementarity in AdS/CFT
Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
We examine the bulk reconstruction in the AdS/CFT correspondence. It is believed that CFT operators in a CFT subregion can construct arbitrary bulk local operators in the bulk subregion associated with the CFT subregion. This correspondence is called the entanglement wedge reconstruction or the subregion duality. We argue that the duality fails to hold by presenting problems existing even in a simple setup (the causal wedge reconstruction). Nevertheless, we propose the subregion complementarity, illustrating that different CFT operators can describe a bulk subregion. While we expect that this complementarity is valid outside the horizon in general eternal black holes, it is inapplicable for single-sided black holes where a semi-classical description at the stretched horizon is absent.
Takahiko Terada, Nagoya U
Dissipative Genesis of the Inflationary Universe
Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
We study an inflation model with a flat scalar potential supported by observations and find that slow-roll inflation can emerge after a quasi-cyclic phase of the Universe, where it undergoes repeated expansions and contractions for a finite time period. The initial conditions and the positive spatial curvature required for such nontrivial dynamics align with the quantum creation of the Universe. The key ingredients that trigger inflation are dissipative interactions of the inflaton, which are necessary to reheat the Universe after inflation and thus give us an observational handle on pre-inflationary physics. Our discovery implies that inflation occurs more robustly after the creation.
Yuta Michimura, RESCEU
Laser interferometric searches for ultralight dark matter
Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
