Quantum Effects in Gravitational Fields

Session

Afternoon session 2

28 Aug 2023, 16:40

Leipzig University

76. Quasinormal modes of Schwarzschild de Sitter black holes from Liouville CFT

Paolo Arnaudo (SISSA)

28/08/2023, 16:40

We consider black hole linear perturbation theory in a four-dimensional Schwarzschild de Sitter background. The relevant differential equation is a Heun equation, which is a second order ODE with four regular singularities. After showing how the exact connection formulae for the Heun equation can be obtained from the semiclassical limit of Virasoro conformal blocks, we use these formulae to...

64. The semiclassical Einstein equation in cosmological spacetimes: Existence and uniqueness of the solutions

Nicola Pinamonti

29/08/2023, 16:40

Contributed talk

During this talk we shall discuss some properties of the semiclassical Einstein equation.
This equation is used to model the backreaction of quantum matter on classical backgrounds.
In this talk we shall in particular analyze the case of backgrounds which describe cosmological spacetimes.
The quantum field we shall consider is massive and satisfies a linear equation with a generic coupling...

41. Graviton couplings on Hilbert space

Christian Gass (University of Warsaw)

30/08/2023, 16:40

Contributed talk

A fresh attempt towards a quantum field theory of gravitons
interacting with matter is based on the Fock space quantization of
Wigner's helicity 2 representation, rather than canonical quantization
of a massless rank-2 tensor field. In this way, all issues with
indefinite state spaces, overshooting degrees of freedom, gauge fixing,
etc. are avoided. It turns out that quantum consistency...

20. Quantum effect unique to gravity based on the weak equivalence principle

Youka Kaku (Nagoya university)

30/08/2023, 16:40

Contributed talk

The construction of a quantum gravity theory remains a challenge. One of the difficulties stems from the lack of sufficient experimental evidence. As a first step toward the quantum gravity experiment, Bose et al. proposed a low-energy experiment to test if Newtonian gravity can generate quantum entanglement or not. However, they assumed that only gravity is mediating in the system, and their...

45. Relative entropy in de Sitter wedges and diamonds

Markus B. Fröb (ITP, Universität Leipzig, Germany)

30/08/2023, 17:00

Contributed talk

The role of entropy, in particular entanglement entropy, in quantum field theory has become increasingly prominent, and entropy has appeared in relation with several primary research topics in QFT: area theorems, c theorems, the AdS/CFT correspondence, quantum null energy inequalities etc. While von Neumann entropy, the basic concept in information theory, is divergent in QFT and can thus only...

35. Towards the optimal experiment of gravity-induced quantum entanglement

Tomohiro Fujita (Waseda Institute for Advanced Study)

30/08/2023, 17:00

Contributed talk

Recently, various experiments have been proposed to verify quantum entanglement induced by Newtonian gravitational interactions. However, no feasible setup has yet been found that is certainly achievable with existing techniques. To search for an optimal setup, we compute the logarithmic negativity of two oscillators with arbitrary quadratic potential and coupled by gravity. We find that...

39. Relative entropy and dynamical black holes

Edoardo D'Angelo (Università di Genova)

30/08/2023, 17:20

Contributed talk

Since the discovery of the Bekenstein-Hawking formula, there had been many attempts to derive the entropy of black holes from the entanglement between the degrees of freedom inside and outside the event horizon. This entanglement entropy reproduces the area-law, but it suffers from divergences in the continuum limit. In this talk, I show how to derive the Bekenstein-Hawking entropy from the...

13. Stress-energy tensor on global anti-de Sitter space-time with Robin boundary conditions

siva namasivayam (University of Sheffield)

30/08/2023, 17:20

Plenary talk

We study the renormalised stress-energy tensor (RSET) for a massless, conformally
coupled scalar field on four dimensional anti-de Sitter space-time (adS4). As ads4 is
not a globally hyperbolic space-time, we impose boundary conditions on the space-time
boundary to have a well posed quantum field theory. We use Dirichlet, Neumann and
Robin (mixed) boundary conditions applied to the scalar...

40. Characteristic renormalization and applications to black hole formation

Daan Janssen (University of Leipzig)

31/08/2023, 16:40

Contributed talk

We present a regularization prescription for Hadamard two-point functions defined on the boundary of a lightcone, which can be used to analyze renormalized quantities for linear scalar fields in a curved background. This can be applied to formulate the semi-classical Einstein equations as a characteristic initial value problem. Furthermore, we shall discuss how these tools can be used to...

47. Cosmological solutions to the semiclassical Einstein equation with Minkowski-like vacua

Nicolai Rothe (rothe@math.tu-berlin.de)

31/08/2023, 17:20

Contributed talk

We will discuss some newly found solutions to the full massless semiclassical Einstein equation (SCE) in a cosmological setting (with Λ=0).
After a short introduction to the relevant notions we present the SCE in a particular shape which allows for the construction of certain vacuum states. These states may be viewed as as the least possible generalization of the Minkowski vacuum to general...

69. Parallel sessions