次回のセミナー (Next Seminar)
AdS Black Hole Quasinormal Modes via Exact WKB (AdS ブラックホールの準固有振動に対する完全 WKB 解析)
| When: | 2026/10/07 (Wed.) 16:00-17:00 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Tomohito Shiga (Rikkyo University) |
| Abstract: | In the AdS/CFT correspondence, black hole quasinormal modes correspond to poles of retarded thermal correlation functions in the boundary theory. In this talk, I will discuss scalar perturbations of global AdS${}_5$-Schwarzschild black holes, focusing on quasinormal modes and correlator pole residues in the small-black-hole, eikonal limit. Starting from connection formulas for Borel-resummed WKB solutions, I will derive the quasinormal-mode condition and evaluate the damping rate, which is nonperturbatively suppressed at large angular momentum. I will then construct the retarded correlator from the same connection formulas and calculate the residues at its quasinormal-mode poles. For angular momentum $\ell \geq 2$, I will evaluate the residues through second order in the small-black-hole parameter $\mu$ and compare them with known results. AdS/CFT対応では、ブラックホールの準固有振動は境界理論の熱的な遅延相関関数の極に対応する。本講演では、global AdS${}_5$-Schwarzschildブラックホール上のスカラー場を対象に、完全WKB解析を用いて小ブラックホール・eikonal極限における準固有振動と相関関数の極の留数を調べる。まず、Borel再和されたWKB解の接続公式から準固有振動の量子化条件を導き、大角運動量で非摂動的に抑制される減衰率を評価する。次に、同じ接続公式から遅延相関関数を構成し、準固有振動の極における留数を計算する。角運動量 $\ell \geq 2$ について、留数を小ブラックホールパラメータ $\mu$ の二次まで求め、既知の結果と比較する。 |
| Reference: | arXiv:2605.01321, ongoing work |
最近のセミナー (Recent Seminars)
TBA
| When: | 2026/11/25 (Wed.) 16:00-17:00 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Jiakang Bao (Science Tokyo) |
| Abstract: | TBA |
| Reference: | TBA |
TBA
| When: | 2026/11/13 (Fri.) 13:30-14:30 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Keisuke Konosu (University of Osaka) |
| Abstract: | TBA |
| Reference: | arXiv:2609.04621 |
Fermionic modes of D-instanton wormholes from broken local supersymmetry
| When: | 2026/10/30 (Fri.) 13:30-14:30 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Shoichi Kawamoto (NITEP, Oberlin University) |
| Abstract: | In low-energy supergravity treatment of type IIB superstring on general D-instanton wormhole profiles in the bulk, we obtain non-vanishing scalar two-point functions in addition to the vanishing $\langle \tau^* \tau^* \rangle$ that corresponds to the BPS amplitude detected by two D-instantons at their respective boundaries. This is exploited to show that the modes of broken local supersymmetry in the bulk deliver the fermionic (diagonal) modes on the boundaries through the deformation by the form of current-current two point functions propagating on the tree level cylinder geometry. Our treatment is generalizable to multi D-instanton cases and general Euclidean branes. |
| Reference: | arXiv:2604.14508 |
Phase Transitions between SUSY and non-SUSY Regimes (超対称真空と非超対称真空の間の相転移)
| When: | 2026/10/21 (Wed.) 16:00-17:00 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Shota Saito (IPMU) |
| Abstract: | Recently, SUSY gauge theories have been used to study the phase structure of strongly coupled non-SUSY gauge theories. The basic strategy is to start from a SUSY theory, where exact results are available, and then introduce SUSY breaking. This approach gives a controlled description near the SUSY limit. A key question is whether a phase transition occurs before the theory reaches the non-SUSY regime. If the vacuum structure or the pattern of global symmetry breaking is different in the two limits, the two regimes cannot be connected smoothly. A phase transition or new infrared dynamics is then required. In this work, we study this problem in truly confining gauge theories. We analyze how the vacuum branches in the SUSY limit are lifted after SUSY breaking. We also determine the resulting pattern of global symmetry breaking. We then compare these phases with those expected in the corresponding non-SUSY theories. We then discuss the phase transition between the SUSY and non-SUSY regimes. Finally, we discuss how generalized symmetries and their ’t Hooft anomalies give constraints on these phase transitions. This seminar assumes basic knowledge of four-dimensional $\mathcal{N}=1$ Yang–Mills theory. 近年、強結合ゲージ理論の相構造を解析的に理解するため、厳密な結果が得られる超対称ゲージ理論を出発点とし、超対称性を破ることで非超対称理論へ接続するアプローチが研究されている。この方法では超対称極限の厳密な低エネルギー記述を利用できる一方、非超対称領域へ向かう途中で相転移が生じるかどうかが重要となる。真空構造や対称性の破れのパターンが両端で異なる場合、両者の間には相転移や新たな赤外理論が必要となる可能性がある。本研究では、この問題を厳密な閉じ込め相を持つ超対称ゲージ理論を用いて調べる。超対称極限に存在する複数の真空分岐がどのように持ち上げられ、どの大域的対称性の破れのパターンが選択されるかを解析する。非超対称理論で期待される相と比較して、両者を補間する過程で相転移が必要となることを議論する。さらに、一般化対称性とそのアノマリーを用いて相転移の必要性をどこまで制約できるかについても展望を述べる。なお、本セミナーでは4次元$\mathcal{N}=1$ Yang–Mills理論の基本事項を前提として議論を進める。 |
| Reference: | arXiv:2608.06093 |
AdS Black Hole Quasinormal Modes via Exact WKB (AdS ブラックホールの準固有振動に対する完全 WKB 解析)
| When: | 2026/10/07 (Wed.) 16:00-17:00 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Tomohito Shiga (Rikkyo University) |
| Abstract: | In the AdS/CFT correspondence, black hole quasinormal modes correspond to poles of retarded thermal correlation functions in the boundary theory. In this talk, I will discuss scalar perturbations of global AdS${}_5$-Schwarzschild black holes, focusing on quasinormal modes and correlator pole residues in the small-black-hole, eikonal limit. Starting from connection formulas for Borel-resummed WKB solutions, I will derive the quasinormal-mode condition and evaluate the damping rate, which is nonperturbatively suppressed at large angular momentum. I will then construct the retarded correlator from the same connection formulas and calculate the residues at its quasinormal-mode poles. For angular momentum $\ell \geq 2$, I will evaluate the residues through second order in the small-black-hole parameter $\mu$ and compare them with known results. AdS/CFT対応では、ブラックホールの準固有振動は境界理論の熱的な遅延相関関数の極に対応する。本講演では、global AdS${}_5$-Schwarzschildブラックホール上のスカラー場を対象に、完全WKB解析を用いて小ブラックホール・eikonal極限における準固有振動と相関関数の極の留数を調べる。まず、Borel再和されたWKB解の接続公式から準固有振動の量子化条件を導き、大角運動量で非摂動的に抑制される減衰率を評価する。次に、同じ接続公式から遅延相関関数を構成し、準固有振動の極における留数を計算する。角運動量 $\ell \geq 2$ について、留数を小ブラックホールパラメータ $\mu$ の二次まで求め、既知の結果と比較する。 |
| Reference: | arXiv:2605.01321, ongoing work |
Quantum Annealing Applied to Atoms and Molecules
| When: | 2026/10/01 (Thu.) 16:00-17:00 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Bhanu Pratap Das (Centre for Quantum Engineering Research and Education TCG CREST) |
| Abstract: | Quantum annealing (QA) is a computational method for solving optimization problems using quantum effects . It was formulated in its current form by Dr. Kadowaki and Prof. Nishimori at the Tokyo Institute of Technology (now Institute of Science Tokyo) in 1998. Their seminal work led to the construction of the first quantum computer based on QA known as quantum annealer by a company in Canada known as D-wave. QA is steadily gaining in importance and has now been applied to a wide range of fundamental and practical problems. An important quantum algorithm in this area is known as the Quantum Annealer Eigensolver (QAE). In my talk, I shall consider recent applications of QAE to atomic and molecular problems and present the results that have been obtained. |
| Reference: |
3d Chern–Simons matter theories from generalized Argyres–Douglas theories
| When: | 2026/07/29 (Wed.) 16:00-17:00 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Yutaka Yoshida (Meiji Gakuin University) |
| Abstract: | 近年、4d $\mathcal{N}=2$ 超共形場理論のSchur指数、あるいは対応するVOAの真空指標のNahm和公式を手がかりとして、3d $\mathcal{N}=2$ Chern--Simons matter理論を構成する一連の研究が行われてきた。このように構成されたChern--Simons matter理論は、適切なモノポール・スーパーポテンシャルを導入することで、赤外領域において超対称性が拡大し、4d $\mathcal{N}=2$ SCFTのある種の3次元簡約(R-twisted reduction)によって得られる3d $\mathcal{N}=4$ 超共形場理論へフローすると考えられている。本講演では、まずこの構成法の一般的な枠組みとその歴史的発展を概観する。その後、我々が行った、$\gcd(M, N)=1$を満たす$(A_{M-1},A_{N-1})$型および$(A_2,D_4)$型Argyres--Douglas理論の3次元簡約を実現するChern--Simons matter理論の構成と、その物理的性質について説明する。 この講演は、西中崇博氏との共同研究 arXiv:2512.15201 [hep-th]、および濱近諒氏、西中崇博氏、谷川昇右氏との共同研究 arXiv:2607.19021 [hep-th]に基づく。 |
| Reference: | arXiv:2512.15201, arXiv:2607.19021 |
Exact WKB analysis of inverted triple-well: resonance, PT-symmetry breaking, and resurgence
| When: | 2026/07/22 (Wed.) 16:00-17:00 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Syo Kamata (The University of Tokyo) |
| Abstract: | We study non-Hermitian quantum mechanics of an inverted triple-well potential within the exact WKB framework. For a single classical potential, different Siegert boundary conditions define three distinct quantum problems: the PT-symmetric, resonance, and anti-resonance systems. For each case, we derive the exact quantization condition and construct the associated trans-series solution. By identifying the resurgent structures and cancellations in these non-Hermitian setups, we obtain the median-summed series, clarifying when the spectra are real or complex in accordance with the physical properties of each system. Establishing explicit links to the semi-classical path integral formalism, we elucidate the roles of bounce and bion configurations in these non-Hermitian systems. This analysis predicts PT-symmetry breaking, which we also verify numerically. Using the median quantization conditions, we prove the existence of this symmetry breaking and establish an exact equation for the exceptional point, which emerges as a remarkably simple algebraic relation between the bounce and bion actions. We further show that the median-summed non-perturbative correction to the spectrum vanishes at the exceptional point, while the resurgent structure survives through a universal minimal trans-series. For the resonance and anti-resonance systems, we find that the exact median-summed spectra are related by complex conjugation, representing time reversal in this setting, are necessarily complex, and do not exhibit an exceptional point. Although their spectra differ significantly from the PT-symmetric case, they share the same minimal trans-series. By maintaining explicit links with the path integral saddles and the formal theory of resurgence, our analysis provides a unified and general perspective on the quantization of non-Hermitian theories. This talk is based on: Syo Kamata and Tatsuhiro Misumi and Cihan Pazarbaşı and Hidetoshi Taya, "Exact WKB analysis of inverted triple-well: resonance, PT-symmetry breaking, and resurgence, " arXiv:2604.05878 [hep-th]. |
| Reference: | arXiv:2604.05878 |
Decrease of the entanglement entropy of the Hawking radiation induced by backreaction in the Bose-Einstein condensate
| When: | 2026/06/12 (Fri.) 12:30-13:30 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Tsunehide Kuroki (Toyota Technological Institute) |
| Abstract: | We analytically study the effect of backreaction from analog Hawking radiation on its entanglement entropy in the Bose-Einstein condensate (BEC). The backreaction is expected to play an essential role in the decrease of the entanglement entropy and in realizing the Page curve. Since the BEC theory has microscopic Hamiltonian and thus exhibits unitarity, it is desirable to reproduce the Page curve explicitly by using the Hamiltonian. As the first step to analyze this in a concrete example, we study the BEC with a step-like configuration that has been extensively studied in the literature. By using the microscopic theory, we derive an explicit form of backreaction from analog Hawking radiation. Combining it with the known results of the Bogoliubov coefficients, we analytically compute the entanglement entropy of the Hawking radiation, and show that it decreases as expected due to the backreaction for sufficiently low energy modes over a wide range of the parameter characterizing the step-like configuration. |
| Reference: | arXiv:2604.14824 |
dS/CFT対応におけるアインシュタイン方程式と第一法則
| When: | 2026/05/29 (Fri.) 12:30-13:30 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Kosei Fujiki (YITP) |
| Abstract: | AdS/CFT対応の枠組みにおいて、アインシュタイン方程式とエンタングルメントエントロピーの第一法則が等価であることが示されている。本講演では、この関係をdS/CFT対応の枠組みで議論する。具体的には、dS時空における計量の一次摂動を考え、線形化アインシュタイン方程式を解く。その解を用いて、適切に第一法則を満たすような、dS/CFT対応におけるエンタングルメントエントロピーの極小曲面の取り方を提案する。本研究は基礎物理学研究所の小原充貴氏、新名宏太朗氏、鈴木優樹氏、高柳匡氏との共同研究に基づく。 |
| Reference: | arXiv:2511.07915 |
More on Higgsing of $D$-type conformal matter from web diagrams
| When: | 2026/05/15 (Fri.) 12:30-13:30 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Hirotaka Hayashi (Tokai University) |
| Abstract: | We revisit Higgsing of $D$-type conformal matter theories compactified on a circle from web diagrams with trivalent gluing. We argue that the Higgsing yields a web diagram for the 5d theory which arises from a circle compactification of the 6d SO(12) gauge theory with half-hypermultiplets in two different spinor representations and also web diagrams for the 5d theories arising from a twisted compactification of the 6d SO(12)/SO(11) gauge theories with spinor matter. It is also possible to apply the topological vertex to the web diagrams and compute the partition functions of the 5d theories. |
| Reference: | ongoing work |
$D$型変形$\mathcal{W}$代数と運動の保存量
| When: | 2026/04/22 (Wed.) 16:00-17:00 |
|---|---|
| Where: | 174 Honkan (Main Bldg.) |
| Speaker: | Michio Jimbo (Rikkyo University) |
| Abstract: | 共形場理論における運動の保存量, およびその$q$変形は, KdV型古典可積分階層のハミルトニアンの量子化にあたる可積分系として興味深い. $\mathfrak{gl}_N$型変形$\mathcal{W}$代数については量子トロイダル代数に基づいた構成が知られているが, $A$型以外についての研究はあまり進んでいない. ここでは問題の背景から始め, $D$型の場合の計算結果を紹介し, その代数的背景を解説する. 本研究は山形大学の小島武夫氏との共同研究である. |
| Reference: | arXiv:2509.23588 |