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Speakers: Alexander Altland (Koeln) and Christian Ecke (Utrecht). Location: Amsterdam.

Event details of Holography: triangle meeting
Date 25 October 2019
Time 13:30 -17:00


13:30 Tea & Coffee

14:00 Alexander Altland (Koeln) - SYK Model - from the perspective of condensed matter

15:15 Coffee break

15:45 Christian Ecke (Utrecht) - Gravitational Waves from Holographic Neutron Star Mergers

17:00 Borrel (drinks and snacks), at Cafe Restaurant Polder (De Paardenstaal). 


Alexander Altland (Koeln) 

SYK Model - from the perspective of condensed matter 

Abstract: Introduced in 2015,  as a candidate for a holographic shadow of a two-dimensional bulk the SYK model has become a paradigm of many body quantum chaos and strong correlations. It displays a plethora of phenomena characteristic for strongly interacting non-integrable many body systems, including exponential instabilities, non-Fermi liquid behavior, chaotic spectral and wave function correlations and, and manifestations of Fock space fractality and localization. At the same time, the SYK model is simple enough to be amenable to sensitive numerical diagnostics and analytic approaches. It is perhaps the only many body chaotic quantum system where parameter free comparison between analytic theories and numerical data is possible, and in this regard has become somewhat of the harmonic oscillator of the field. In this talk I will review the physics of the SYK model, emphasis put on its internal symmetries which make analytic progress possible. I will discuss both, the physics at short times governed by strong chaotic instabilities, and that at long times, or small energies, where the intricate fine structures of its many body eigenenergies and -functions are resolved. While much of this discussion draws on the toolset of condensed matter physics and chaos, the results bear consequences in the holographic context, which other attendants of the workshop may be more qualified to judge.

Christian Ecker (Utrecht) 

Gravitational Waves from Holographic Neutron Star Mergers 

Abstract: We simulate the merger of binary neutron stars and analyze the spectral properties of their gravitational waveforms. For the stars we construct hybrid equations of state (EoSs) with a standard nuclear matter EoS at low densities, transitioning to a state-of-the-art holographic EoS in the otherwise intractable high density regime. Depending on the transition density the characteristic frequencies in the spectrum produced from the hybrid EoSs are shifted to significantly lower values as compared to the pure nuclear matter EoS. The highest rest-mass density reached outside a possible black hole horizon is approximately 1.1 * 10^15 g/cm^3, which for the holographic model is below the density of the deconfined quark matter phase.


G2.10, Science Park 904, Amsterdam.



This event is part of a regular series of meetings sponsored by Delta ITP with the objective of bringing together the theoretical physics communities in Amsterdam, Leiden, Utrecht and our sister nodes Groningen, Brussels (ULB and VUB), Leuven and Mons. The topic of this meeting is holography and its applications to different physical systems. We encourage researchers from different areas in theoretical physics to participate!


Diego Hofman Uv Amsterdam
Umut Gursoy Utrecht Un.
Koenraad Schalm Leiden Un.