ELFT HÍRADÓ

[tcsaba <tcsaba AT eik.bme.hu>]

                 M E G H Í V Ó - I N V I T A T I O N

    Seminar Series of the Department of Theoretical Physics at the
           Budapest University of Technology and Economics


                          Bruno Bertini
                     (University of Ljubjana)


      Exact Spectral Form Factor and Entanglement Spreading
          in a Minimal Model of Many-Body Quantum Chaos


I will show that the periodically driven Ising chain in transverse 
field, for some particular values of the couplings, can be regarded as a 
minimal model for many body quantum chaos. Specifically, I will present 
an exact proof of the fact that the spectral form factor (a measure of 
spectral correlations) is described by random matrix theory. This result 
implies ergodicity for any finite amount of disorder in the longitudinal 
field, excluding the possibility of many-body localisation. The method 
used provides a novel route for obtaining exact non-perturbative results 
in non-integrable systems. As an example of this, I provide exact 
results on the entanglement spreading from a class of initial states and 
use that to characterise the entanglement spreading in the system.

References:
B. Bertini, P. Kos, and T. Prosen, arXiv:1812.05090
B. Bertini, P. Kos, and T. Prosen, Phys. Rev. Lett. 121, 264101(2018)


Időpont: 2019. március 1. péntek, 10:15
Helyszín: BME Fizikai Intézet, Elméleti Fizika Tanszék,
Budafoki út 8. F-épület, III lépcsőház, szemináriumi szoba