Welcome address Room: Amphitheater Alkis Argyriadis

Non supersymmetric strings and the (in)stabilities of their vacua

• Augusto Sagnotti

Room: Amphitheater Alkis Argyriadis

Pseudospectra of Holographic Quasinormal Modes

• Karl Landsteiner (Unknown)

Room: Amphitheater Alkis Argyriadis Quasinormal modes and frequencies are the eigenvectors and eigenvalues of a non-Hermitian differential operator. They are of crucial importance in the physics of black holes. The analysis of quasinormal modes in asymptotically Anti-de Sitter geometries plays also a key role in the study of strongly coupled quantum many-body systems via gauge/gravity duality. In contrast to normal Sturm-Liouville operators, the eigenvalues of non-Hermitian (and non-normal) operators generally exhibit instability under small perturbations. After a brief review of quasinormal modes I will discuss the stability analysis of quasinormal frequencies for asymptotically planar AdS black holes based on pseudospectrum analysis. Specifically, we concentrate on the pseudospectra of scalar and transverse gauge fields, shedding light on their relevance within the framework of gauge/gravity duality.

On non-supersymmetric string models

• John Rizos (Nuclear Physics Laboratory)

Room: Amphitheater Alkis Argyriadis

Two dimensional black holes and matrix quantum mechanics

• Olga Papadoulaki

Room: Amphitheater Alkis Argyriadis

Natural Alignment Beyond the Standard Model

• Apostolos Pilaftsis (University of Manchester)

Room: Amphitheater Alkis Argyriadis

Probing the deep string spectrum

• Chrysoula Markou

Room: Amphitheater Alkis Argyriadis

PTA gravitational waves and James Webb early galaxies: from Primordial Black Holes to Axion Clusters

• Sokratis Trifinopoulos

Room: Amphitheater Alkis Argyriadis Recent observations have granted to us two unique insights into the early universe: the presence of a low-frequency stochastic gravitational wave background detected by the NANOGrav and Pulsar Timing Array (PTA) experiments and the emergence of unusually massive galaxy candidates at high redshifts reported by the James Webb Space Telescope (JWST). In this talk, I will consider the possibility that both observations have a common origin. First, I will scrutinize primordial black holes (PBHs) in the mass range between 10^6 and 10^13 solar masses. While superheavy PBHs act as seeds of accelerated galaxy formation capable of explaining the JWST extreme galaxies, they can also form binary mergers that source gravitational waves which can be potentially identified as the PTA signal. The analysis is performed taking into account the constraints on the relevant region of the PBH parameter space including the novel bound imposed by the so-called Ultraviolet Luminosity Function (UV LF) of galaxies observed by the Hubble Space Telescope. Then, I will discuss minicluster seeds in the initial axion density field due to the decay of the axion string network in the post-inflationary scenario. For axions heavier than 10^(-25) eV , the resulting clusters have a significant impact on large-scale structure, which is also strictly constrained by the UV LF.

Stochastic dynamics from quantum field theory

• Spyros Sypsas

Room: Amphitheater Alkis Argyriadis The partition function of a scalar field theory can be computed order by order in the interaction potential within perturbative quantum field theory. We will show that when there exists a separation of scales, the statistics of the long/slow field-modes obey a Fokker-Planck equation exhibiting nonstandard probability drift and diffusion due to short/fast dynamics. Our main application will be scalar physics on de Sitter space (where the Hubble radius provides the required scale separation) but the results extend to any open system with this property.

Lessons from discrete light-cone quantization for gravitational physics on null hypersurfaces

• Glenn Barnich

Room: Amphitheater Alkis Argyriadis

Quantum systems as manipulators of information: Entanglement, complexity, and phases of matter

• Georgios Styliaris

Room: Amphitheater Alkis Argyriadis

New Light on Light Dark Sectors

• Josef Prandler

Room: Amphitheater Alkis Argyriadis

Bootstrability with improved truncation methods

• Vasilis Niarchos

Room: Amphitheater Alkis Argyriadis

Entangled Universe

• Nikolaos Tetradis

Room: Amphitheater Alkis Argyriadis

Gauge Invariance at Large Charge

• Pantelis Panopoulos

Room: Amphitheater Alkis Argyriadis

Corrections to electroweak vacuum decay in metric-affine gravity

• Ioannis Gialamas

Room: Amphitheater Alkis Argyriadis

Anisotropic scale-separated AdS flux vacua

• George Tringas

Room: Amphitheater Alkis Argyriadis