Program
Conference Venue:
June 30: C1124, 11th floor, Building C, Material Science & Research Building, East Capmus of USTC
科大东区物质科研楼C楼11层C1124
July 1-3: Peach Blossoms Pond Hall, 4th floor of Anhui Hotel
安徽饭店4楼桃花潭
Registration: June 29
Opening: June 30, 9:00-9:10
* Online talk
Titles & Abstracts:
Chris Hull
Title: Superstring Field Theory
James Liu
Title: Surprises in higher derivative supergravity
Abstract: Higher derivative corrected supergravities play an important role in precision holography and black hole physics. While, in principle, constructing higher derivative superinvariants ought to be straightforward, in practice surprises can arise. In this talk I will focus on four-derivative couplings in five-dimensional N=2 supergravity. In the minimal supergravity, there is a unique supersymmetric completion of the Riemann-squared coupling. However, new F^4 invariants can be constructed in the presence of additional vector multiplets. Somewhat surprisingly, these four-derivative corrections provide an obstruction to the decoupling of the vector multiplets in the four-derivative theory that is not present at thetwo-derivative level.
Gautam Mandal
Title: Entanglement entropy puzzles for c=1 matrix model and lowest Landau level fermions
Abstract: The entanglement entropy of c=1 matrix models is finite whereas it is divergent in collective field theory which is purportedly dual to 2D string theory. We describe an exact bosonic dual which is inherently defined on a lattice and reproduces the finite entropy. This sheds some possible insight into entropy in string theory. A similar bosonization helps us understand a puzzle concerning 2D fermions in a magnetic field (the Landau problem).
Sungjay Lee
Title: Resurgence of the Thermal Transition between Bounce and Sphaleron
Abstract: We study the thermaltransition between the bounce and the sphaleron in quantum mechanicswith a metastable vacuum from the viewpoint of Borel resurgence. Fortwo models representing a second-order and a first-order transition,we compute the perturbative expansion of the thermal free energy tohigh orders and extract the leading Borel singularity data (A, b, S)as functions of temperature. The Borel singularity location A reproducesthe on-shell action of the dominant saddle on both sides of the transition,joining smoothly in the second-order case and developing a kink in thefirst-order case. The characteristic exponent b jumps between 0 and1/2 across the transition, counting the zero modes of the correspondingsaddle. The Stokes constant S matches the one-loop determinant aroundthe saddle. The perturbative expansion around the false vacuum thusdetermines the transition temperature, the order of the transition,and the decay rate including the one-loop prefactor without relyingon semiclassical inputs.
Qiang Jia
Title: Non-perturbative Gauge Anomalies and Instantons
Abstract: In this talk, I will revisit anomalous phases related to large gauge transformations, such as the Witten anomaly. The latter, known to plague 4D $Sp(k)$ theories, is well-understood in terms of 4th homotopy group of $Sp(k)$, but it also has an oblique relation to the instantons, labeled by 3rd homotopy group, via the fermion zero mode counting. I will revisit this relation and point out how SU(N) theories escape an anomalous sign of the latter type, thanks to the perturbative anomaly cancelation condition that restricts the chiral fermion spectrum. This leads to the question of what happens if the latter, more mundane anomaly is canceled by an inflow instead. We explore two models of such a kind, the Witten and Yonekura setup, and also the fractional D3 probe theories in type IIB theory, and show that they are free from the anomalous sign of the fermion zero mode counting.
Shlomo S. Razamat
Title: Going against the flow with supersymmetric QFTs
Abstract: We consider the space of supersymmetric conformal field theories (SCFTs) in 4d. Many, conjecturally all, 4d SCFTs can be engineered by reductions of 6d SCFTs on Riemann surfaces. Thus the space of 4d SCFTs can be covered by overlapping patches labeled by 6d SCFTs. We will first review how one can associate a system of commuting relativistic quantum mechanical (QM) Hamiltonians to such patches and the relation of these systems to supersymmetric index computations. Next, we will discuss examples of non-relativistic limits of the QM models and the corresponding indices. We will claim that the further free limits of these non-relativistic models can be thought of as generalizations of the powerful N=2 Schur index to the more general N=1 setups. We will discuss some of the surprising properties these free indices satisfy: e.g. in some cases the indices of theories down the RG flow know information about the theories up the RG flow which naively they do not entitled to know. The talk is based mainly on https://arxiv.org/abs/2604.19885 and https://arxiv.org/abs/2506.13764.
Seok Kim
Title:Comments on quantum black hole cohomologies
Abstract: I will discuss the 1-loop lifts of some classical supercharge cohomologies for the 1/16-BPS black hole microstates in AdS5 xS5. I will also discuss by how much the classical cohomologies over-estimate the entropy of absolutely protected 1/16-BPS states in the Cardy limit.
Hee-Cheol Kim
Title: 6d Supergravity Blocks
Abstract: I will present a bottom-up framework for constructing 6d (1,0) supergravity theories from supergravity blocks. Each block is a basic unit built from a little string theory sector associated with the H-string, together with the external BPS generators attached to it, and is characterized by carrying intrinsic gravitational tensors. As a first application, I will give the classification of non-Higgsable gravity blocks and discuss candidate supergravity theories that arise in this framework but have no realization in ordinary F-theory geometry.
Gary Shiu
Title: Euclidean Wormholes and the Swampland
Shuang-Yong Zhou
Title: Bootstraping the Veneziano amplitude analytically
Abstract: We analytically prove that the Veneziano amplitude is the unique outcome of a dual bootstrap based on dispersive sum rules, unitarity, and a small amount of additional stringy input. This stringy input can be either the string monodromy condition or the recently uncovered splitting and hidden-zero conditions. A key ingredient in our proofs is to interpret the dispersive sum rules as sequences of moments. Also important is the precise incorporation of the extra stringy input into the amplitude ansatz. Together, these ingredients make the bootstrap analytically tractable and uniquely fix the Veneziano amplitude.
Xi-Nan Zhou
Title: Cosmological Correlators Using Tensor Networks
Abstract: In this talk, I will introduce a nonperturbative tensor network framework for computing cosmological observables in a controlled lattice realization of interacting QFT in 2d de Sitter spacetime. I will use this framework to test the recent proposal that suitably defined in-in correlators can be obtained from an in-out formalism by gluing the expanding and contracting Poincare patches. I will report nonperturbative evidence for the proposed equivalence in phi-4 theory in both heavy and light field regimes, and comment on regulator subtleties associated with the singular behavior near the patching surface. I will also comment on various extensions of this numerical framework.
Finn Larsen
Title: Phases of AdS supergravity
Eric Bergshoeff
Title: A Unifying Approach to Galilei and Carroll Symmetries
Abstract: We show that two basic properties of Galilei symmetries can be extended, against common belief, to Carroll symmetries when properly interpreted. The first property is the fact that one can take critical Galilei limits using the fact that the Galilei algebra can be centrally extended to a Bargmann algebra. We demonstrate that, although the Carroll algebra does not allow such a central extension, one can nevertheless formulate a critical Carroll limit provided one allows for Euclidean or spacelike branes. The second property of Galilei symmetries is the fact that one can obtain systems with Bargmann symmetry by performing a null reduction over a spatial dimension. We show that similarly critical Carroll systems can be obtained by performing a Carrollian version of the null reduction over a time direction. In the supersymmetric case the resulting theories can be identified with critical Carroll limits of the star supergravities introduced by Hull.
Leopoldo Pando Zayas
Title: Low-Temperature Quantum Corrections in Holography
Abstract: Near-extremal black holes are known to contain strong quantum fluctuations in their near-horizon near-AdS2 throat region governed by an effective action that includes Schwarzian modes. These fluctuations lead to one-loop corrections in the gravitational path integral that are essential in understanding the thermodynamics of near-extremal black holes at low temperatures where they become more dominant that the semi-classical answer. In this talk we will review the universality of such one-loop analysis from tensor modes through a mathematical proof that applies to asymptotically flat, Anti-de-Sitter and de-Sitter black holes; it also covers spherical, axial and planar symmetries. We will also review some implications of these quantum fluctuations for transport coefficients computed in the near-extremal asymptotically AdS4 black branes in the context of the AdS/CFT correspondence. For example, at one-loop level there is a coupling of the shear gravitational fluctuations to one of the would-be zero modes and this coupling affects the retarded Green’s function in a way that leads to a low temperature violation of the shear viscosity to entropy density bound.
Kantaro Ohmori
Title: Topological lines in 1+1d chiral fermions
Abstract: I will talk about a construction of topological lines in 1+1d holomorphic CFT in terms of symmetry TFT. In particular, the method is applied to a construction of topological lines in the chiral free fermion theory that intertwines the global symmetry currents nontrivially. Upon folding, this construction in turn provides a boundary condition in the non-chiral fermion theory that preserves a not-vector-like anomaly-free symmetry. Based on an on-going work with Masataka Watanabe.
Yi-Fan Wang
Title: Exploring Defect Renormalization Group Flows
Abstract: Defects provide powerful probes of quantum field theory. Supported on lower-dimensional subspaces, they host their own degrees of freedom, generalize ordinary local operator algebras, and exhibit novel phases connected by renormalization group flows. Defect dynamics is particularly rich when the bulk system is gapless and described by a conformal field theory (CFT). We will discuss modern developments in the study of defects in CFT, including their interplay with symmetries and anomalies, and comment on how they encode structural information about the ambient CFT.
Yi-Nan Wang
Title: On E7+1/2 gauge theory
Wei Song
Title: An exact solvable Carrollian fermion model
Chi-Ming Chang
Title: Protected BMN Sectors and Black-Hole Microstates
Abstract: BMN matrix quantum mechanics is a mass deformation of the BFSS matrix modelthat lifts the flat directions, providing a controlled setting for studyingprotected sectors of D0-brane holography. In this talk I will explainhow protected quantities in BMN matrix quantum mechanics can be usedto probe black-hole microstates. I will first review the relation betweenBFSS/BMN matrix quantum mechanics and D0-brane black holes, emphasizinghow the BMN deformation lifts the flat directions and makes protectedcounting well-defined. I will then describe the finite-N BMN Wittenindex across vacuum sectors, where the all-sector computation exhibitsan N^2 entropy signal and identifies the vacuum sectors that dominatethe protected count. Finally, I will discuss why Q-cohomology containsfiner information than the index, as well as a mass-flow argument showingthat BMN Q-cohomology is invariant under changes of the mass parameterat nonzero mass, subject to analytic domain control. The broader goalis to use protected BMN sectors as a sharp window into the microscopicstructure of holographic black holes.
Zhen-Bin Yang
Title: Quantum Chaos and Wormholes
Abstract: I will give a review about recent progress to understand the connection between quantum chaos and wormholes.