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A: Fachverband Atomphysik
A 12: Poster I
A 12.3: Poster
Dienstag, 7. März 2023, 16:30–19:00, Empore Lichthof
Dynamical phase transition in an open quantum system — •Julian Feß1, Ling-Na Wu2, Jens Nettersheim1, Alexander Schnell2, Sabrina Burgardt1, Silvia Hiebel1, Daniel Adam1, André Eckardt2, and Artur Widera1 — 1Department of Physics and State Research Center OPTIMAS, RPTU Kaiserslautern, 67663 Kaiserslautern, Germany — 2Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
Phase transitions correspond to the singular behavior of physical systems in response to continuous control parameters. Recently, dynamical quantum phase transitions have been observed in the non-equilibrium dynamics of isolated quantum systems, with time as the control parameter. However, signatures of such dynamical phase transition in open systems, were so far elusive. Here, we demonstrate that dynamical phase transitions can also occur in open quantum systems. We measure the relaxation dynamics of the large atomic spin of individual Caesium atoms induced by the dissipative coupling via spin-exchange processes to an ultracold Bose gas of Rubidium atoms. For initial states far from equilibrium, the entropy of the spin state is found to peak in time, transiently approaching its maximum possible value, before eventually relaxing to its lower equilibrium value. Moreover, a finite-size scaling analysis shows that it corresponds to a dynamical phase transition. Our results show that dynamical phase transitions are not restricted to occur in isolated systems, but, surprisingly, are possible also during the dissipative evolution of open quantum systems.