University of Crete HEP Seminars
QFT in AdS instead of LSZ
| Speaker: | Balt van Rees |
| Institution: | Ecole Polytechnique |
| Time: | 4 February 2025, 13:15 |
| Venue: | Webinar |
| Abstract: | Consider a conformally covariant four-point function of identical scalar operators with a discrete spectrum, a twist gap, and compatible with the unitarity conditions. We give a mathematical proof confirming that the spectrum and OPE coefficients at large spin and fixed twist always become that of a generalized free field theory. |
| Recording: | The recorded talk can be found here. |
A microscopic description of ds3
| Speaker: | Lorenz Eberhardt |
| Institution: | Amsterdam U. |
| Time: | 11 February 2025, 13:15 |
| Venue: | Webinar |
| Abstract: | I will explain a proposal for relating pure Einstein gravity with positive cosmological constant in 2+1d to a matrix model. The matrix model is capable of reproducing all the integrated cosmological correlators in the bulk as well as the exact de Sitter entropy. Based on 2501.01486 in collaboration with Scott Collier and Beatrix Mühlmann. |
| Recording: | The recorded talk can be found here. |
Exploring Boundary Effects in TTbar-deformed Quantum Field Theories
| Speaker: | Roberto Tateo |
| Institution: | Turin U. |
| Time: | 18 February 2025, 13:15 |
| Venue: | Webinar |
| Abstract: | In this seminar, we will explore the properties of the TTbar deformation --a distinctive integrable deformation built from components of the stress-energy tensor -- in the context of two-dimensional quantum field theories. While the bulk properties of TTbar-deformed theories are now well understood, thanks to their connections with coordinate transformations and topological gravity models, their behavior in the presence of boundaries and defects remains a largely uncharted territory. We will review recent analytical advancements, focusing on the exact g-function of TTbar deformed theories, derived using the Thermodynamic Bethe Ansatz (TBA) and verified through solutions to a Burgers-type flow equation. This comparison highlights a remarkable consistency between different approaches. The talk will conclude with a discussion of open problems and promising directions for future research in this evolving field. |
| Recording: | The recorded talk can be found here. |
Gravitational Collapse at the Boundary
| Speaker: | David Mateos |
| Institution: | Barcelona U. |
| Time: | 20 February 2025, 13:15 |
| Venue: | Webinar |
| Abstract: | Holography has provided valuable insights into the time evolution of strongly coupled gauge theories in a fixed spacetime. However, this framework is insufficient if this spacetime is dynamical. We present a scheme to evolve a four-dimensional, strongly interacting gauge theory coupled to four-dimensional dynamical gravity in the semiclassical regime. We apply this framework to the description of the gravitational collapse and the subsequent formation of a black hole at the boundary. In the bulk, this corresponds to the formation of a black funnel. If time permits, we will also use holography to study the so-called BKL dynamics near the singularity behind the black hole horizon. |
| Recording: | The recorded talk can be found here. |
Quasinormal ringdown of chaotic systems
| Speaker: | Matthew Dodelson |
| Institution: | CERN |
| Time: | 25 February 2025, 13:15 |
| Venue: | Webinar |
| Abstract: | I will discuss the late time behavior of thermal correlators in chaotic systems. Under certain assumptions, the thermal two point function exhibits exponential decay, with a discrete spectrum of complex frequencies. I will explain how these frequencies can be thought of as quasinormal modes of a black hole whose radial direction is identified with complexity. This perspective leads to an efficient method for computing the spectrum, and also a better understanding of the analytic structure. I will give various examples, mostly in the context of holography or the SYK model, where explicit computations can be done. |
| Recording: | The recorded talk can be found here. |
Looking at extremal black holes from far away
| Speaker: | Gustavo Joaquin Turiaci |
| Institution: | Washington U. |
| Time: | 4 March 2025, 17:15 |
| Venue: | Webinar |
| Abstract: | In the first part of this talk I review recent progress clarifying some physical aspects of the extremal limit of black holes. I describe two puzzles that arise from a semiclassical treatment of near-extremal black hole thermodynamics. Both puzzles are resolved by realizing that quantum gravity effects become arbitrarily large at low temperatures. In the second part, I will describe some recent work clarifying the origin of these quantum effects from the gravitational path integral. Finally, I will describe ongoing work on identifying similar effects in certain cosmological setups. |
| Recording: | The recorded talk can be found here. |