Dresden 2020 – wissenschaftliches Programm
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DY 48.7: Vortrag
Donnerstag, 19. März 2020, 11:15–11:30, ZEU 147
Ageing and non-markovian effects in the exactly solved quantum O(n)-model — •Sascha Wald1, Alessio Chiocchetta2, Malte Henkel3, and Andrea Gambassi4 — 1Max-Planck-Institut für Physik Komplexer Systeme, Nöthnitzer Straße 38, 01187, Dresden, Germany — 2Institute for Theoretical Physics, University of Cologne, 50937 Cologne, Germany — 3Laboratoire de Physique et Chimie Théoriques (CNRS UMR 7019), Université de Lorraine Nancy, B.P. 70239, 54506 Vandoeuvre lès Nancy, France — 4SISSA - International School for Advanced Studies and INFN, via Bonomea 265, I-34136 Trieste, Italy
The effects of quantum noise on the non-equilibrium dynamics of many-body quantum systems, after a quantum quench, are analysed. Quantum noise, as opposed to the classical white noise, is inherently non-Markovian and the resulting dynamics is affected by memory effects, which lead to changes compared to Markovian white noises. In order to systematically analyse these effects, we study the quantum O(n)-model at large n, in contact with a bath at zero temperature. Starting from the quantum Langevin equation, the dynamical equations are explicitly solved. The universal properties of the dynamics, as given by the quantum noise and after a quantum quench, are analysed by studying the two-time correlation and response functions. Quantum coarsening and quantum ageing in these observables are highlighted and compared with their classical counterparts. In particular, the validity of the fluctuation-dissipation theorem after a quantum quench is studied in detail.