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arXiv · 2506.05770

Dynamical Phase Transition of Dissipative Fermionic Superfluids

Abstract

Driven-dissipative open quantum many-body systems exhibit rich phases that are characterized by the steady states in the long-time dynamics. However, lossy open systems inevitably decay to the vacuum, making their transient evolution the primary focus. Assuming the Hartree-Fock-Bogoliubov ansatz, we derive a generalized time-dependent Hartree-Fock-Bogoliubov equation based on the least action principle for open quantum systems. By solving the quench dynamics after abruptly introducing inelastic scattering or one-body loss in the Bardeen-Cooper-Schrieffer limit, we reveal a generic dynamical phase transition: the superfluid order parameter vanishes non-analytically while the superfluid fraction's first-order time derivative undergoes a discontinuous change at a finite critical time. This marks a new paradigm of dynamical phase transitions, distinct from those in closed systems, where the initial state must be finely tuned.

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Xin-Yuan Gao, Yangqian Yan. 2025-06-06. Dynamical Phase Transition of Dissipative Fermionic Superfluids. https://arxiv.org/abs/2506.05770

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