Black Holes, Quantum Chaos, and Quantum Information

Recently, the study of quantum black holes has significantly advanced due to the progress in our understanding of gravitational path integral of Euclidean wormholes and the Schwarzian degree of freedom, as well as various the applications of theory of quantum information, quantum chaos and the random matrix theory. The purpose of this workshop is to exchange ideas and have active discussions, to bring further progress to this exciting research area.

The highlighted topics include

1. Non-perturbative Hilbert space for BH and closed universes 

2. Near extremal BH and its dynamics, in particular approach from Schwarzian

3. Trace relations in gravity and structure of BPS states

4. Quantum information and quantum chaos in holography

Invited Speakers

Chi-ming Chang (Tsinghua)

Yiming Chen (Stanford)

Felix Haehl (Southampton)

Veronika Hubeny (UC Davis)

Luca Iliesiu (UC Berkeley)

Seok Kim (Seoul National)

Ji Hoon Lee (ETH Zurich)

Beatrix Muehlmann (IAS)

Kazumi Okuyama (Shinshu)

Mukund Rangamani (UC Davis)

Sandip Trivedi (Tata)

Cynthia Yan (Stanford)

Schedule

May 26 Mon

9:30-11:00 Registration

11:00-12:15 Seok Kim: "Black hole microstates from gauge theories"

I will review the old and recent studies of black hole microstates from free and weakly-coupled gauge theories. Qualitative and (semi-)quantitative results from the thermal partition functions, indices and explicit operator constructions will be discussed, with an emphasis on the roles of trace relations to understand the spectrum of large operators. 

12:15-14:00 Lunch (+poster set-ups)

14:00-15:05 Contributed talks

Lee Eunwoo (TIFR): "AdS Black Holes at Large Angular Momentum and Large Charge " (30 min)

Fast-rotating AdS black holes develop superradiant instabilities, and we conjecture that they evolve into Grey Galaxies—critically spinning central black holes encircled by a light-speed disk of thermal bulk gas. Charged AdS₅×S⁵ black holes also exhibit superradiant instabilities. We propose that their endpoint is a Dual Dressed Black Hole (DDBH): an AdS core surrounded by one to three dual giant gravitons, with corresponding SO(6) chemical potentials set to unity. We briefly describe the supersymmetric versions of both Grey Galaxies and DDBHs.

Li Yixuan (Padua): "The Statistics of BPS Chaos" (15 min)

Black hole microstates, considered collectively as an ensemble, are believed to exhibit properties of quantum chaos, and in particular eigenvalue repulsion. The extent of the repulsion characterises how ‘strong’ the chaos is. In this talk, I will focus on the example of the microstates of a supersymmetric black holes with macroscopic horizon, namely the D1-D5-P system. I will explain how the ability to find ‘strong’ or ‘weak’ chaos is related to how the microstates are organised into some particular subgroups, similar to what has been recently found by Chen, Lin and Shenker for black holes with vanishing-area horizon. Finally, I will show how this organisational problem translates into a statistical-mechanics problem and discuss the physical implications. (Work in progress with N. Ceplak, S. Massai and M. Shigemori.)

Jan Boruch (Berkeley): "Indices from the gravitational path integral: new forms of attraction" (20 min)

In recent years, the Euclidean gravitational path integral has proven to be a reliable tool for studying quantum mechanical aspects of black holes. An important quantity that can help us probe whether black holes behave like conventional quantum mechanical systems is the supersymmetric index computed directly from the gravitational path integral. In this talk, I will discuss the issue of multicentered black hole contributions to the Euclidean path integral that computes the supersymmetric index at finite temperature. In the context of Einstein-Maxwell theory in 4d, I will explain how the multicentered generalization of the Kerr-Newman black hole, called the Israel-Wilson solution, can be seen to satisfy the boundary conditions of the supersymmetric index and yields a regular contribution to the index. I will show how even though we perform the computations at finite temperature, the construction makes the value of the on-shell action depend only on the black hole charges, which can be viewed as a new form of the attractor mechanism. Finally, I will describe how we can extend the analysis to the most general solutions of N=2 4d supergravity, where the on-shell action becomes independent of the boundary values of the scalars. Time permitting, I will describe how the phenomenon of wall-crossing, in which the index jumps discontinuously as one crosses a codimension one wall in the space of asymptotic scalar moduli, arises from the perspective of the new finite temperature saddles. Based on 2310.07763 and 2501.17909 with Roberto Emparan, Luca Iliesiu, Sameer Murthy, and Joaquin Turiaci.

15:20-16:20 Contributed talks

Weyne Weng (Cornel): "A single geometry from an all-genus expansion in quantum gravity" (30 min)

In this talk, I report on an instance in quantum gravity where a topological expansion resums into an effective description on a single geometry. The original theory whose gravitational path integral we study is JT quantum gravity with one asymptotic boundary at nonperturbatively low temperatures. The effective theory we derive is a deformation of JT gravity by a highly quantum and nonlocal interaction for the dilaton, evaluated only on a disk topology. This emergent description addresses a strongly quantum gravitational regime where all genera contribute at the same order, successfully capturing the doubly nonperturbative physics of the original theory. This talk is based on 2412.08799 and on-going work with Sergio Hernández-Cuenca and Nico Valdes-Meller.

Akihiro Miyata (YITP): "Quantum error correction and black hole interior with a gravitating bath system" (15 min)

We investigate quantum error correction properties in a setup where a black hole is entangled with a gravitating bath, modeled by the doubled PSSY model. When treating errors in the bath system without considering gravitational back-reaction, the quantum error correction properties remain quantitatively similar to those of a non-gravitating bath. However, when we include gravitational back-reaction from errors (treated as local operators) in the bath system, we find that the resulting quantum error correction properties deviate from both the non-gravitating case and the gravitating case without back-reaction.

Wen Qiang (Southeast): "The entanglement structure of a holographic state has a universal two-point correlation description" (15 min)

I will show that, in the vacuum of a holographic CFT, the entanglement structure at leading order can be fully described by a two-point correlation structure. Under a proper geomtrization scheme, this structure reproduces the Crofton formula in Poincare AdS. This case further implies the equivalence between the Crofton formula and two-point correlation structure. The validity of the Crofton formula for a generic Riemann manifold implies that, the existence of a two-point correlation structure which can fully describe the entanglement structure of a holographic state at leading order is universal. 

16:30-17:45 Poster Session 1 (Link is here)

May 27 Tue

9:30-10:45 Ji Hoon Lee: "Comments on Finite N in AdS3 x S3 x M4" 

I will discuss how to reproduce the integer spectrum of chiral primaries in the symmetric orbifold at finite N by summing over one-loop partition functions of an infinite set of bulk geometries that are asymptotic to AdS3 x S3 x T4 or K3.

11:15-12:30 Beatrix Muehlmann: "Toward a microscopic realization of dS_3"

I will discuss a recent proposal of a precise duality between pure (2+1)-dimensional de Sitter quantum gravity and a double-scaled matrix integral. There are two main aspects of this correspondence. First, by discussing the canonical quantization of the gravitational phase space, I will arrive at a novel proposal for the quantum state of the universe at future infinity, which differs from the usual no-boundary proposal. I will then discuss the computation of cosmological correlators of massive particles in the universe specified by this wavefunction. Remarkably, these integrated cosmological correlators are precisely computed by the string amplitudes of the recently-introduced complex Liouville string (CLS), thereby establishing a direct connection between the cosmological correlators and resolvents of the matrix integral dual of CLS. The second aspect of the duality involves the Gibbons-Hawking entropy of the cosmological horizon of the de Sitter static patch. I will show that the de Sitter entropy can be reproduced exactly by counting degrees of freedom in the matrix model dual.

12:30-14:00 Lunch

14:00-15:15 Felix Haehl: "Modular-invariant random matrix theory and AdS3 wormholes "

I will propose a non-perturbative definition of RMT2: a generalization of random matrix theory that is compatible with the symmetries of 2d CFT. Given any random matrix ensemble, its spectral correlations admit a modular-invariant lift to RMT2, which reduce to the original random matrix correlators in a near-extremal limit. The lift proceeds in two steps: I will first discuss a Mellin space formulation of RMT. The Mellin space correlators are then interpreted as an SL(2,Z) spectral decomposition. This sheds a new light on the AdS3 wormhole geometries with multiple torus boundaries.

15:45-17:05 Contributed talks

Ricardo Schiappa (IST University of Lisbon): "Exact Solutions to Matrix Models and String Theories"  (30 min)

Recent developments in resurgence and transseries have uncovered the full non-perturbative content of large classes of matrix models and string theories, which turn out to include both branes and negative-tension branes (holding for all hermitian one-matrix models, minimal strings and JT gravity, and dual Dijkgraaf-Vafa topological string theories). On top, they have allowed for the exact computation of Stokes data for all these models. This talk will discuss how one may assemble all this information into rather compact formulae for the exact partition functions of all these models. Alongside the aforementioned Stokes data, such formulae allow for exact analytical interpolations, from weak to strong 't Hooft coupling, from weak to strong string coupling, including all values anywhere on their complex domains, which may be compared against numerical data with remarkable precision.

Gabriel Di Ubaldo (Berkeley & Riken): "Modular-invariant random matrix theory and AdS3​ wormholes" (15 min)

We develop a non-perturbative definition of RMT22​: a generalization of random matrix theory that is compatible with the symmetries of two-dimensional conformal field theory. Given any random matrix ensemble, its nn-point spectral correlations admit a prescribed modular-invariant lift to RMT22​, which moreover reduce to the original random matrix correlators in a near-extremal limit. Central to the prescription is a presentation of random matrix theory in Mellin space, which lifts to two dimensions via the SL(2,Z)SL(2,Z) spectral decomposition employed in previous work. As a demonstration we perform the explicit RMT22​ lift of two-point correlations of the GUE Airy model. We propose that in AdS33​ pure gravity, semiclassical amplitudes for off-shell nn-boundary torus wormholes with topology Σ0,n×S1Σ0,n​×S1 are given by the RMT22​ lift of JT gravity wormhole amplitudes. For the three-boundary case, we identify a gravity calculation which matches the RMT22​ result.

Masataka Watanabe (Tokyo): "Large-charge Renyi entropy" (15min)

We find universal behavior in charged (symmetry-resolved) Renyi entropy of a certain class of three-dimensional strongly-coupled CFT in the large charge limit. The method involves using the effective field theory apprach known as the large-charge expansion, while the result is the (first?) holography-free computation of quantum information theoretic quantity in higher-dimensional strongly-coupled CFTs.

Taishi Kawamoto (YITP): "A Strategy for Proving the Strong Eigenstate Thermalization Hypothesis: Chaotic Systems and Holography" (15min)

The strong eigenstate thermalization hypothesis (ETH) provides a sufficient condition for thermalization and equilibration. Although it is expected to hold in a wide class of highly chaotic theories, there are only a few analytic examples demonstrating the strong ETH in special cases, often through methods related to integrability. In this talk, I will explore sufficient conditions for the strong ETH that may apply to a broad range of chaotic theories. These conditions are expressed as inequalities involving the long-time averages of real-time thermal correlators. Specifically, I will discuss bottom-up holographic models that satisfy these conditions under certain assumptions, which are expected to hold in such models. This talk is based on the preprint 2411.09746 [hep-th].

17:15-18:30 Poster Session 2 (Link is here)

May 28 Wed

9:30-10:45 Luca Iliesiu: " The gravitational path integral from an observer's point of view "

One of the fundamental problems in quantum gravity is to describe the experience of a gravitating observer in generic spacetimes. In this talk, I will describe a framework within which we can analyze non-perturbative physics relative to an observer using the gravitational path integral. We apply our proposal to an observer that lives in a closed universe and one that falls behind a black hole horizon. We find that the Hilbert space that describes the experience of the observer is much larger than the Hilbert space in the absence of an observer. In the case of closed universes, the Hilbert space is not one-dimensional, as calculations in the absence of the observer suggest. Rather, its dimension scales exponentially in 1/G_N. Similarly, from an observer's perspective, the dimension of the Hilbert space in a two-sided black hole is increased and this drastically changes what an observer sees when falling past the horizon of a black hole at late times.

11:15-12:30 Kazumi Okuyama: "Recent developments in double-scaled SYK"

SYK model is an interesting toy model of holographic duality. In particular, the so-called double-scaled SYK (DSSYK), which is defined by taking a large N limit with the number p of the p-body interaction scaled as p=N^(1/2),  has attracted a lot of attention recently since DSSYK is exactly solvable thanks to the underlying quantum group symmetry. In this talk, I will briefly review the recent developments in DSSYK.

12:30-18:00 Free discussion

May 29 Thu

9:30-10:45 Chi-ming Chang: "Exploring Quantum Gravity Microstates via Q-cohomology"

I will introduce the supercharge Q-cohomology in holographic quantum field theories, which capture properties of supersymmetric black holes in the dual gravity theory. The Q-cohomology classes fall into two categories: monotone and fortuitous, and are holographically dual to microstates of horizonless geometries and black holes, respectively. I will then explore various properties of black holes via fortuitous classes in the N=4 super-Yang-Mills (SYM) theory and the D1-D5 CFTs. 

11:15-12:30 Yiming Chen: "Fortuity in SYK models"

The notion of "fortuitous" states has recently been introduced to characterize the microstates of supersymmetric (BPS) black holes, distinguishing them from the "monotone" microstates of horizonless geometries. In this talk, I will explore the notion of fortuity in SYK models. For generic choices of couplings, all the BPS states in these models are fortuitous. These models reveal a close connection between fortuity and the Schwarzian effective description of near-BPS black holes. Additionally, I will discuss generalized models that contain both fortuitous and monotone states. I will use these toy models to demonstrate distinct quantum chaotic properties of the two types of states. If time permits, I will also discuss some follow-up ideas.

12:30-14:00 Lunch

14:00-15:15 Mukund Rangamani: "Strings and near-extremal black holes in AdS3 "

I will describe features of superstring theory in AdS3 backgrounds.  I will outline how the one-loop partition function reproduces the supergravity spectrum (in the semiclassical limit) and encodes the boundary supergravitons.  Of particular interest will the regime where the AdS curvature is at the string scale, which we will be able to access within the conventional RNS formalism in one example. I will explain that how the tensionless string discussed in the literature differs from the one obtained by taking a suitable limit of our construction, and explain the origin of this difference. Finally, I will describe how the string partition function can be used to understand the thermodynamics of near-extremal BTZ black holes, and in particular recover the BPS index in an appropriate limit. 

15:45-16:45 Contributed Talks

Marija Tomasevic (Amsterdam): "From black holes to strings, with spin" (30 min)

Statistical features of certain black holes can be understood in terms of stringy degrees of freedom. We provide evidence that such a correspondence between black holes and strings will hold even when angular momentum is taken into account. In particular, the sizes of spinning strings seem to match non-trivially to those of black holes, providing stronger evidence in favor of the correspondence framework.

Hong Zhe Chen (Santa Barbara): "Observers seeing gravitational Hilbert spaces: abstract sources for an abstract path integral" (30 min)

The gravitational path integral suggests a striking result: the Hilbert space of closed universes in each superselection sector, a so-called alpha-sector, is one-dimensional. We develop an abstract formalism encapsulating recent proposals that modify the gravitational path integral in the presence of observers and allow larger Hilbert spaces to be associated with closed universes. Our formalism regards the gravitational path integral as a map from abstract objects called sources to complex numbers, and introduces additional objects called partial sources, which form sources when glued together. We apply this formalism to treat, on equal footing, universes with spatial boundaries, closed universes with prescribed observer worldlines, and closed universes containing observers entangled with external systems. In these contexts, the relevant gravitational Hilbert spaces contain states prepared by partial sources and can consequently have nontrivial alpha-sectors supporting non-commuting operators. Within our general framework, the positivity of the gravitational inner product implies a bound on the Hilbert space trace of certain positive operators over each alpha-sector. The trace of such operators, in turn, quantifies the effective size of this Hilbert space.

17:00-17:30 Contributed Talks

Shima Kazunari (Saitama Institute of Technology): "Implication of Nonlinear Supersymmetric General  Relativity" (15 min)

On (unstable) Riemann space-time whose tangent space possesses NLSUSY structure, i.e., specified by Majorana spinor（fermionic coordinates） ψαi (i=1…N)　for SL(2,C) besides the ordinary Minkowski coordinates xa for SO(1,3) we find the unified vierbein waμ and performing the ordinary geometric argument of the general relativity we obtain straightforwardly new Einstein-Hilbert(EH)-type action (Nonlinear-supersymmetric general relativity(NLSGR)) LNLSGR (waμ) with the cosmological term and the global NLSUSY invariance.  NLSUSY structure of space-time  LNLSGR (waμ)   would  break down(Big collapse) to the ordinary EH action for graviton eaμ,  NLSUSY action for Goldstone(G) fermion ψαi (primodial matter, superon) and their gravitational interaction which is called superon-graviton action LSGM. (eaμ ψαi ).

Simultaneously the universal attractive force graviton would dictate the evolution(vaccum) of LSGM (eaμ, ψαi) by producing all possible gravitational massless composites of superons corresponding to the supermultiplet fields of supergravity(N-extended SUGRA) of spsce-time symmetry, which is the ignition of the Big Bang of the universe. 

As shown in the simple toy model, NLSGR paradigm bridges naturally the cosmology and the low energy particle physics, which  provides new insights into unsolved problems of cosmology, SM and  mysterious relations between them, e.g. the space-time dimension four, the origin of SUSY breaking, the dark energy and the dark matter, the dark energy density≃( neutrino mass)4 , the three-generations structure of quarks and leptons, the rapid expansion of space-time, the antiparticle disappearance in nature and the fate of black hole etc. All results were published separately. 

For some details and references,  [Ref.]  [1] K. Shima, Invited talk at the symposium, 100 Years Werner Heisenberg-Works and Impact-, September 26-30, Bamberg, Germany. Proceeding: Fortschr. Phys. 50 (2002) 5-7,717, eds. D. Leust and W. Schleich.  [2] K. Shima, Invited talk at Conference on Cosmology, Gravitational Waves and Particles ,2017, NTU, Singapore (Uploaded at YouTube by IAS). Proceedings  of CCGWP, ed. Harald Fritzsch, (World Scientific, Singapore, 2017), 301. [3] K. Shima, Temporal preliminary report: arXiv:2012.01646[hep-th]

Seiji Terashima (YITP): "Bulk reconstruction and subregion in AdS/CFT" (15 min)

We investigate how the quantum gravity theory emerges from the CFT (bulk reconstruction) when considering a subregion in the context of AdS/CFT. The study of subregions is crucial for understanding quantum gravity, particularly in areas such as black hole physics. Notably, we demonstrate that even in simple subregions, such as the AdS-Rindler patch, bulk local operators cannot be fully reconstructed—an outcome that contradicts conventional wisdom. Specifically, while a bulk reconstruction reproducing the two-point function exists, we show that higher-point functions, such as the three-point function, become ill-defined.

17:30-18:15 Poster Session 3 (Link is here)

May 30 Fri

9:30-10:45 Veronika Hubeny: "Correlation Hypergraph and Marginal Independence"

We introduce an efficient representation of the patterns of marginal independence (which encapsulate all pairwise-decorrelated subsystems) based on certain correlation hypergraphs.  These constructs generalize to arbitrary quantum systems the holographic relation between positivity of mutual information and connectivity of entanglement wedges.  In the holographic context these enable us to formulate a necessary condition for the realizability of entropy vectors by simple tree graph models, which in turn provide the building blocks for the holographic entropy cone.

11:15-12:30 Cynthia Yan: "Puzzles in 3D Off-Shell Geometries via VTQFT"

We point out a difficulty with a naive application of Virasoro TQFT methods to compute path integrals for two types of off-shell 3-dimensional geometries. Maxfield-Turiaci proposed solving the negativity problem of pure 3d gravity by summing over off-shell geometries known as Seifert manifolds. We attempt to compute Seifert manifolds using Virasoro TQFT. Our results don't match completely with Maxfield-Turiaci. We trace the discrepancies to not including the mapping class group properly. We also compute a 3-boundary torus-wormhole by extrapolating from an on-shell geometry. We encounter challenges similar to those observed in the comparison between the genuine off-shell computation of a torus-wormhole by Cotler-Jensen and the extrapolation from an on-shell configuration.

12:30-14:00 Lunch 

14:00-15:05 Contributed Talks

Masaki Tezuka (Kyoto): "Two-local modifications of the Sachdev-Ye-Kitaev model with quantum chaotic energy spectra" (20min)

The four-local interaction of fermions in the Sachdev-Ye-Kitaev (SYK) model makes quantum simulation challenging. We argue that the four-local interaction may not be important by introducing models with two-local interactions: a qudit generalization of the spin-SYK model and various clusters SYK models (arXiv:2505.09900).

Hugo Camargo (Gwangju Institute of Science and Technology): Operator growth in holographic CFTs  (15min)

Motivated by bulk reconstruction of smeared boundary operators, we study the Krylov complexity of local and non-local primary CFT operators from the local bulk-to-bulk propagator of a minimally-coupled massive scalar field in Rindler-AdS space. We derive analytic and numerical evidence on how the degree of non-locality in the dual CFT observable affects the evolution of Krylov complexity and the Lanczos coefficients. We also show that the evolution of the growth rate of Krylov operator complexity in the CFT takes the same form as to the proper radial momentum of a probe particle inside the bulk to a good approximation. Our results capture a prosperous interplay between Krylov complexity in the CFT, thermal ensembles at finite bulk locations and their role in the holographic dictionary.

Luis Apolo (Beijing Institute of Mathematical Sciences and Applications): "Logarithmic corrections to black hole entropy and the asymptotics of weak Jacobi forms" (15 min)

I will discuss the asymptotic growth of states in weak Jacobi forms (wJfs) with features motivated by the AdS3/CFT2 correspondence. At leading order, this growth follows Cardy’s formula, reproducing the entropy of certain BPS black holes. I will then consider subleading corrections to Cardy’s formula, identifying conditions under which these corrections are universal or depend on the spectrum of light states. In the context of black holes, these subleading terms correspond to logarithmic corrections to their entropy, and I will show how wJfs encode these corrections in different scenarios.

Vipul Kumar (TIFR): "Grey Galaxies in AdS5" (15 min)

It has recently been conjectured that the end point of the rotational super-radiant instability of black holes in AdS4 is a Grey Galaxy: an ω = 1 black hole sitting at the centre of AdS4, surrounded by a large disk of rapidly rotating gravitons and other bulk fields. In this paper we study Grey Galaxies in AdS5. In this case, the rotational group is of rank 2, and so has two distinct angular velocities ω1 and ω2. We demonstrate that AdS5 hosts two qualitatively distinct Grey Galaxy phases: the first with either ω1 ≈ 1 or ω2 ≈ 1, and the second with both angular velocities ≈ 1. We use these results to present a conjecture for a part of the phase diagram of N = 4 Yang-Mills (as a function of energy and the two angular momenta) that displays several phase transitions between regular black holes and various Grey Galaxy phases. We present an explicit gravitational construction of the phases in which ω1 and ω2 are both parametrically close to unity, and demonstrate that the corresponding boundary stress tensor is the sum of two pieces. The first is the stress tensor of the central black hole. The second - the contribution of the bulk gas - takes the form of the stress tensor of an equilibrated boundary conformal fluid, rotating at the given angular speeds ωi. We also briefly comment on the structure of Grey Galaxies in AdSD for D > 5.

15:20-16:20 Contributed Talks

Karl Jonathan (Wurzburg):  "Black Hole Microstates and the Factorisation puzzle" (15min)

In holography, two manifestations of the black hole information paradox are given by the non-isometric nature of the bulk-boundary map and by the factorisation puzzle. By considering time-shifted microstates of the eternal black hole, we demonstrate that both these puzzles may be simultaneously resolved by taking into account non local quantum corrections that correspond to wormholes arising from state averaging. This is achieved by showing, using a resolvent technique, that the resulting Hilbert space for an eternal black hole in Anti-de Sitter space is finite-dimensional with a discrete energy spectrum. The latter gives rise to a transition to a type I von Neumann algebra.

Takato Mori (Rikkyo): "Complexity of purification in random matrix theory" (15min)

How is a complexity of a mixed state quantified? We challenge this problem in the Krylov formalism, in which complexity is interpreted as how large an operator/state spreads in the operator/state space as time evolves. Purification enables us to calculate the spread complexity even for mixed states. In addition, this defines several different complexities, which are mutually related by conjectured inequalities with the operator complexity. We demonstrate the hierarchical relation in one and two qubits and random matrix theory. This talk is based on an updated version of https://arxiv.org/abs/2408.00826 appearing soon in arXiv.

Sergio Emest Aguilar Gutierrez (OIST): "Chord Fusion Geometry, Multiple Shocks and Switchback in Double-Scaled SYK" (15min)

We investigate the geometric interpretation of chord fusion and construct interior states with an intertwining property. This enables the generation of Lin–Stanford bulk states with matter insertions from boundary states of fixed energy or temperature. Using these states, we derive exact results for chord diagrams involving multiple crossings in the bulk. We then develop path integral techniques that, in the semiclassical limit, describe single and multiple shockwave configurations in an AdS$_2$ black hole background. Combining these tools, we derive precise conditions under which the switchback effect is realized, in terms of the total chord number in the DSSYK, which can be interpreted in terms of Krylov operator complexity. Thus, our work elucidates the structure of chord amplitudes with multiple operator insertions; its bulk interpretation in terms of q-deformed shockwave geometries; and on the derivation of the switchback effect in the DSSYK model. Based o work in progress with Jiuci Xu.

Yu-ki Suzuki (YITP): "Holographic Entanglement in the FLRW spacetime" (15 min)

We compute the holographic entanglement entropy in the FLRW spacetime via Ryu-Takayanagi formula. We impose the strong subadditivity and discuss when it is satisfied.

16:35-17:50 Sandip Trivedi: "JT gravity in deSitter Space and Its Extensions"

We will discuss the canonical quantisation of JT gravity in deSitter space and related ideas. 

Poster Guideline

The size of a poster board is 86.8cm (width) and 151.5cm (height). Each presenter can use one board. Magnets will be provided.

Registration

Registration is closed.

Venue

The workshop will be held at Panasonic Auditorium, Yukawa Hall, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto, Japan. Please check the "Access maps" in the YITP webpage. 

Organizers

Masamichi Miyaji (YITP), Tokiro Numasawa (University of Tokyo), Tadashi Takayanagi (YITP), Kotaro Tamaoka (Nihon), Zhenbin Yang (Tsinghua)

About this workshop

This workshop is "YITP International Workshop Led by Young Researchers" supported by YITP. 

Acknowledgement

If your research was benefitted from discussions/talks/new collaborations during this workshop, please acknowledge YITP, as it will help organizing workshops in the future. 

Example:

The authors thank the Yukawa Institute for Theoretical Physics at Kyoto University, where this work was initiated [partially done/completed] during the YITP-I-25-01 on "Black Hole, Quantum Chaos and Quantum Information".