Dissipative dynamics of a driven quantum spin coupled to a bath of ultracold fermions

TL;DR

This paper investigates the driven dynamics and steady states of a quantum spin coupled to ultracold fermionic baths, revealing tunable dissipation effects, bound state phenomena, and potential steady-state magnetization inversion.

Contribution

It introduces a model for a driven quantum spin interacting with ultracold fermions, demonstrating how experimental tuning affects dissipation and steady-state properties.

Findings

Radio-frequency driving modifies Rabi oscillations.

Tuning scattering length controls spin-bath coupling.

Emergence of magnetization inversion in steady state.

Abstract

We explore the dynamics and the steady state of a driven quantum spin coupled to a bath of fermions, which can be realized with a strongly imbalanced mixture of ultracold atoms using currently available experimental tools. Radio-frequency driving can be used to induce tunneling between the spin states. The Rabi oscillations are modified due to the coupling of the quantum spin to the environment, which causes frequency renormalization and damping. The spin-bath coupling can be widely tuned by adjusting the scattering length through a Feshbach resonance. When the scattering potential creates a bound state, by tuning the driving frequency it is possible to populate either the ground state, in which the bound state is filled, or a metastable state in which the bound state is empty. In the latter case, we predict an emergent inversion of the steady-state magnetization. Our work shows that different regimes of dissipative dynamics can be explored with a quantum spin coupled to a bath of ultracold fermions.