Triangle Seminars
Monday, 28 Nov 2022
LonTI: Introduction to Black Hole Microstate Counting
Sameer Murthy
(King's College London)
Abstract:
The pioneering work of Bekenstein and Hawking in the 1970s showed that black holes have thermodynamic properties like temperature and entropy in the quantum theory, just like the air in this room. This leads to the question: can we account for the thermodynamic entropy of a black hole as a statistical entropy of an ensemble of microscopic states? One of the big successes of string theory is to answer this question in the affirmative for a large class of black holes.
The pioneering work of Bekenstein and Hawking in the 1970s showed that black holes have thermodynamic properties like temperature and entropy in the quantum theory, just like the air in this room. This leads to the question: can we account for the thermodynamic entropy of a black hole as a statistical entropy of an ensemble of microscopic states? One of the big successes of string theory is to answer this question in the affirmative for a large class of black holes.
Posted by: lonti
Tuesday, 29 Nov 2022
Positivity in EFTs with spontaneously broken boosts
Oliver Janssen
(ICTP, Trieste)
Abstract:
I will discuss positivity bounds on EFT coefficients in theories where Lorentz boosts are spontaneously broken. The well-known S-matrix argument from the Lorentz-invariant scenario does not straightforwardly generalize to this case. Instead the analytic properties of the retarded Green’s function of conserved currents (or of the stress-energy tensor) will be used, and the theory will be assumed to become conformal in the UV. The method is general and applicable to both cosmology and condensed matter systems. As a concrete example we will consider the EFT of conformal superfluids, which describes the universal low-energy dynamics of CFTs at large U(1) charge, and we will derive inequalities on the coefficients of the operators, in three spacetime dimensions, at NLO and NNLO.
I will discuss positivity bounds on EFT coefficients in theories where Lorentz boosts are spontaneously broken. The well-known S-matrix argument from the Lorentz-invariant scenario does not straightforwardly generalize to this case. Instead the analytic properties of the retarded Green’s function of conserved currents (or of the stress-energy tensor) will be used, and the theory will be assumed to become conformal in the UV. The method is general and applicable to both cosmology and condensed matter systems. As a concrete example we will consider the EFT of conformal superfluids, which describes the universal low-energy dynamics of CFTs at large U(1) charge, and we will derive inequalities on the coefficients of the operators, in three spacetime dimensions, at NLO and NNLO.
Posted by: IC
Thursday, 1 Dec 2022
Gravity amplitudes, w 1+inf and color-kinematic
📍 London
Alfredo Guevara
(Harvard)
Abstract:
W-algebras are ubiquitous extended symmetries of a vast class of CFTs, with deep connections to quantum groups and integrability. Recently, through the techniques of celestial holography, the W_{1+inf} algebra was realized explicitly in celestial correlation functions associated to 4d gravitational scattering amplitudes, but the connection to other realizations of the symmetry, and in particular integrability, was vaguely understood. In this talk I will attempt to shed some light on this issue, arguing that the emergence of the symmetry is directly connected to the color-kinematics duality relating gravity and gauge theory amplitudes, at the same time unveiling an associative structure in collinear singularities of the tree-level S-Matrix.
W-algebras are ubiquitous extended symmetries of a vast class of CFTs, with deep connections to quantum groups and integrability. Recently, through the techniques of celestial holography, the W_{1+inf} algebra was realized explicitly in celestial correlation functions associated to 4d gravitational scattering amplitudes, but the connection to other realizations of the symmetry, and in particular integrability, was vaguely understood. In this talk I will attempt to shed some light on this issue, arguing that the emergence of the symmetry is directly connected to the color-kinematics duality relating gravity and gauge theory amplitudes, at the same time unveiling an associative structure in collinear singularities of the tree-level S-Matrix.
Posted by: QMW
Effective description of quantum chaos and applications to black holes
📍 London
Felix Haehl
(Southampton)
Abstract:
After reviewing different aspects of thermalization and chaos in holographic quantum systems, I will argue that universal aspects can be captured using an effective field theory framework that shares similarities with hydrodynamics. Focusing on the quantum butterfly effect, I will explain how to develop a simple effective theory of the 'scramblon' from path integral considerations. I will also discuss applications of this formalism to shockwave scattering in black hole backgrounds in AdS/CFT.
After reviewing different aspects of thermalization and chaos in holographic quantum systems, I will argue that universal aspects can be captured using an effective field theory framework that shares similarities with hydrodynamics. Focusing on the quantum butterfly effect, I will explain how to develop a simple effective theory of the 'scramblon' from path integral considerations. I will also discuss applications of this formalism to shockwave scattering in black hole backgrounds in AdS/CFT.
Posted by: andrea