C. Artiaco: Signatures of many-body localization in the dynamics of two-level systems in glasses 

TITOLO: Signatures of many-body localization in the dynamics of two-level systems in glasses
SPEAKER: Claudia Artiaco, Royal Institute of Technology - KTH, Stockholm, Sweden
DATA: 30 novembre 2022 - ore 17.00
LUOGO: Aula Seminari del Dipartimento di Fisica [Cubo 31C, Piano IV]
ABSTRACT: In this talk, I will present a recent work on the quantum dynamics of two-level systems (TLSs) in glasses at ultra-low temperatures (1 K and below). We study an ensemble of TLSs coupled with a phonon bath. In the weak coupling limit, by integrating out the phonons within the framework of the Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) master equation, we find that the dynamics of the TLS system at short and intermediate time scales presents clear signatures of many-body localization physics. In particular, we observe a power-law decay of the concurrence - which measures the pairwise entanglement also in non-isolated systems - even in the presence of dissipation, if the latter is not too large. These features can be ascribed to the strong, long-tailed disorder characterizing the distributions of the model parameters. In addition, I will show that the localized transient regime in the TLS dynamics is also present in the limit in which TLSs and phonons are strongly coupled. Remarkably, the signatures of localization should be experimentally accessible in real glassy samples at ultra-low temperatures, using for instance ultra-fast laser probes. Hence, our findings show that glasses might be a privileged platform for probing many-body localization in real materials.