Superradiance Induced Particle Flow via Dynamical Gauge Coupling.

Area of Science:

• Quantum optics
• Condensed matter physics
• Many-body physics

Background:

• Fermions coupled to cavity modes exhibit novel quantum phenomena.
• Raman-assisted hopping in one-dimensional lattices is a key mechanism for studying light-matter interactions.
• Superradiance in driven open quantum systems offers pathways to directed particle flow.

Purpose of the Study:

• Investigate the superradiant phase and particle flow in a one-dimensional lattice model.
• Explore the effects of finite lattice size and boundaries on nonequilibrium dynamics.
• Characterize the steady-state properties in the presence of cavity fluctuations.

Main Methods:

• Theoretical modeling of gauge-coupled fermions in a cavity.
• Analysis of Raman-assisted hopping in a one-dimensional lattice.
• Nonequilibrium dynamical simulations including fluctuation effects.

Main Results:

• An infinite lattice exhibits a superradiant phase with a low pumping threshold, driving directed particle flow.
• Finite lattices display short-time dynamics dominated by superradiance and long-time behavior governed by cavity fluctuations.
• The steady state in finite lattices is non-unique and characterized by coherent bosonic excitations.

Conclusions:

• Superradiance in driven fermionic systems can establish directed particle flow.
• Cavity fluctuations play a crucial role in determining the long-time steady-state behavior of finite systems.
• The unique steady states are linked to emergent bosonic excitations above the Fermi surface.