École Normale Supérieure Summer Institute 2026

Liste des Contributions

1. The third law of black hole mechanics

Harvey Reall

25/06/2026 11:00

The third law of black hole mechanics asserts that it is impossible for a non-extremal black hole to become extremal in finite time (in classical General Relativity). Counterexamples were found recently: gravitational collapse of a massless charged scalar field can produce an exactly extremal Reissner-Nordstrom black hole in finite time, passing through an intermediate phase in which the...

2. Braneworld holography from TTbar flows

Nele Callebaut

25/06/2026 14:00

I will present our systematic study of braneworld holography, with a focus on the 3D/2d case, in which we identify what has been referred to as the 'cut-off CFT' in braneworld holography literature with a $T\bar T$-deformed CFT, and the effective gravity theory on the brane with a $T\bar T$-like deformed timelike Liouville theory. In the limit of the brane approaching the asymptotic boundary,...

4. The black hole at the end of the cone: localizing the anomaly polynomial on toric geometries

Davide Cassani

26/06/2026 11:00

Anomalies are known to govern the asymptotic growth of states in CFTs through Cardy-like formulae and to play a central role in the thermodynamics of BPS black holes. In this talk, we discuss a new manifestation of this connection. We consider five-dimensional supergravity, gauged or ungauged, and propose a method based on equivariant integration of the anomaly polynomial to evaluate the...

6. Descending into the Modular Bootstrap

Jesse Thaler

26/06/2026 14:00

The modular bootstrap has been a powerful tool for carving out the landscape of allowed two-dimensional conformal field theories (CFTs). In this talk, I describe a complementary approach to standard modular bootstrap bounds: using modern machine learning strategies to actively search for CFT spectra that yield a valid torus partition function. Using insights from statistical inference and a...

8. Bounds on Symmetry Breaking and other Swampland Constraints

Irene Valenzuela

29/06/2026 11:00

7. Observing quantum gravity at macroscopic horizon scales

Roberto Emparan

29/06/2026 14:00

It has often been assumed that quantum gravity effects near a macroscopic black hole horizon should be strongly suppressed due to the enormous hierarchy between the horizon scale and the Planck scale, and that any observable deviations would require highly speculative or poorly controlled non-local physics. However, it has recently become clear that this expectation can fail in a controlled...

5. From trees to loops in celestial CFT

Andrea Puhm

29/06/2026 15:30

Symmetries impose powerful constraints on the structure of theories that are holographical dual to quantum gravity in the bulk spacetime. I will review recent progress on the structure of two-dimensional celestial CFTs conjectured to be dual to quantum gravity in four-dimensional asymptotically flat spacetimes where the set of symmetries underlying the universality of gravitational scattering...

12. Thermal entropy and entanglement transitions from modular objects

Erik Tonni

30/06/2026 14:00

The reduced density matrix of a spatial subsystem can be written as the exponential of the modular Hamiltonian (a.k.a. entanglement Hamiltonian) and its eigenvalues provide the entanglement entropy. Hence, this operator contains a lot of information about the entanglement of the corresponding spatial bipartition. Within Algebraic Quantum Field Theory, the modular Hamiltonian and the modular...

9. Multiparty entanglement and holography

Simon Ross

30/06/2026 15:30

Entanglement plays a central role in our understanding of the emergence of spacetime in holography. There is growing evidence that many holographic states have significant multiparty entanglement. I will discuss some signals of multiparty entanglement, and their behaviour in holographic states.

11. Detector Amplitudes and Positivity Bounds

Brando Bellazini

01/07/2026 11:00

Long-range interactions in four-dimensional flat spacetime pose a challenge for positivity bounds and S-matrix bootstrap programs, because infrared divergences trivialize ordinary scattering amplitudes. In this talk, I will introduce stripped, or detector, amplitudes: IR-finite avatars of standard amplitudes that retain analyticity, crossing symmetry, and Regge boundedness, while depending on...

10. Interfaces in Symmetric Product Orbifolds and Holography

Volker Schomerus

01/07/2026 14:00

Conformal interfaces are attracting growing attention across quantum field theory, holography, and integrability. While interfaces in higher-dimensional gauge theories—such as gauge-group-changing interfaces in N=4 super Yang–Mills theories—have been studied extensively, much less is known about interfaces in symmetric orbifold conformal field theories.

Symmetric product orbifolds are a...

14. CFT in AdS and boundary criticality

Simone Giombi

02/07/2026 11:00

By conformally mapping a boundary conformal field theory (BCFT) to anti-de Sitter space, one obtains a natural framework for studying boundary critical phenomena. The different conformal boundary conditions of the CFT, corresponding to distinct boundary universality classes, have a natural description in AdS, which also provides a powerful approach for the calculation of various BCFT...

13. Quantum corrections to near extremal black hole thermodynamics

Chiara Toldo

02/07/2026 15:00

In this talk I will describe how recently developed techniques allow to compute the quantum corrections to the entropy of near-extremal black holes, by regularizing certain zero-modes appearing in the gravitational path integral in the near horizon geometry. I will show that the quantum-corrected near-extremal entropy exhibits 3/2 log T behavior characteristic of the Schwarzian model, and...

15. On bulk reconstruction in Lorentzian AdS and its flat space limit

Ana-Maria Raclariu

03/07/2026 10:00

We revisit the reconstruction of a free scalar in 4-dimensional Lorentzian Anti-de-Sitter spacetime in terms of primary operators in the boundary 3d CFT. We show that the positive and negative energy subspaces of solutions to the Klein–Gordon equation in AdS can be spanned with bulk-to-boundary propagators with appropriate time orderings. As a result, free scalar fields on a codimension-1 bulk...

16. Two Applications of SSB in AdS

Lorenzo Di Pietro

03/07/2026 11:30

I will discuss the definition and the consequences of Spontaneous Symmetry Breaking (SSB) for a quantum field theory on a rigid Anti-de Sitter (AdS) background. In particular I will review the existence of a (trivial) conformal manifold, and explain how to compute its metric from the two-point function of the bulk current. I will then discuss two applications: (1) to quantum electrodynamics in...