# SKM 2023 – wissenschaftliches Programm

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# DY: Fachverband Dynamik und Statistische Physik

## DY 30: Nonequilibrium Quantum Many-Body Systems II (joint session TT/DY)

### DY 30.5: Vortrag

### Mittwoch, 29. März 2023, 16:00–16:15, HSZ 204

**Ultrafast dynamics of cold Fermi gas after a local quench** — Nikolay Gnezdilov^{1}, •Andrei Pavlov^{2,3}, Vladimir Ohanesjan^{4}, Yevheniia Cheipesh^{4}, and Koenraad Schalm^{4} — ^{1}Department of Physics, University of Florida, Gainesville, USA — ^{2}The Abdus Salam International Centre for Theoretical Physics (ICTP) Strada Costiera 11, Trieste, Italy — ^{3}Institut für QuantenMaterialien und Technologien, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, Germany — ^{4}Instituut-Lorentz, Universiteit Leiden, Leiden, The Netherlands

We consider energy dynamics of two initially independent reservoirs A and B filled with a cold Fermi gas coupled and decoupled by two quantum quenches following one another. The energy change in the system adds up the heat transferred between A and B and the work done by the quench to uncouple the reservoirs. In case when A and B interact for a short time, we find an energy increase in both reservoirs upon decoupling. This energy gain results from the quenches' work and does not depend on the initial temperature imbalance between the reservoirs. We relate the quenches' work to the mutual correlations of A and B expressed through their von Neumann entropies. Utilizing this relation, we show that once A and B become coupled, their von Neumann entropies grow (on a timescale of the Fermi time) faster than thermal transport within the system. For a metallic setup, this implies the characteristic timescale of correlations' growth to be in the femtosecond range, while for the ultracold atoms, we expect it to be in the millisecond range.