Bonn 2025 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 1: Atomic Systems in External Fields I

A 1.4: Vortrag

Montag, 10. März 2025, 12:15–12:30, KlHS Mathe

Fluctuation-induced Bistability of Fermionic Atoms Coupled to a Dissipative Cavity — •Luisa Tolle¹, Ameneh Sheikhan¹, Thierry Giamarchi², Corinna Kollath¹, and Catalin-Mihai Halati² — ¹Physikalisches Institut, University of Bonn, Germany — ²DQMP, University of Geneva, Switzerland

We investigate the steady state phase diagram of fermionic atoms subjected to an optical lattice and coupled to a high finesse optical cavity with photon losses. The coupling between the atoms and the cavity field is induced by a transverse pump beam. Taking fluctuations around the mean-field solutions into account, we find that a transition to a self-organized phase takes place at a critical value of the pump strength.

In the self-organized phase the cavity field takes a finite expectation value and the atoms show a modulation in the density.

Surprisingly, at even larger pump strengths two self-organized stable solutions of the cavity field and the atoms occur, signaling the presence of a bistability. We show that the bistable behavior is induced by the atoms-cavity fluctuations and is not captured by the the mean-field approach.

Keywords: light-matter coupling; fermions; open system; bistability; out-of-equilibrium