Non-Thermal Effects in Fermionic Atoms Coupled to Open Cavities

Jules Sueiro; Marco Schiro

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arXiv · 2609.20434

Non-Thermal Effects in Fermionic Atoms Coupled to Open Cavities

Jules Sueiro·Marco Schiro

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Abstract

We study a Fermi-Hubbard model coupled to a open dissipative single cavity mode. Using Keldysh diagrammatics we derive and solve the quantum kinetic equations for the fermions, taking the bosonic cavity mode as a source of non-equilibrium noise and dissipation. In absence of Hubbard interactions we show that the fermions reach generically a non-equilibrium steady-state, characterized by a non-thermal distribution function. Quite interestingly we demonstrate that the latter exactly nullifies the heat-current between fermions and cavity mode. We discuss the regimes of parameters where a low-frequency effective temperature description emerges and how the fluctuations affect the mean-field phase diagram for the superradiance phase transition. Finally we include Hubbard interaction in the weak-coupling regime and show that it leads to a crossover towards a full equilibrium distribution.

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Jules Sueiro, Marco Schiro. 2026-09-17. Non-Thermal Effects in Fermionic Atoms Coupled to Open Cavities. https://arxiv.org/abs/2609.20434

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