Dissipative Phase Transition in Central Spin Systems

TL;DR

This paper explores the phase transitions in an open central spin system with coherent interactions, driving, and dissipation, revealing complex steady-state behaviors and potential experimental observations.

Contribution

It introduces a self-consistent Holstein-Primakoff method to analytically map the phase diagram of dissipative central spin systems, including various phase transitions and bistability.

Findings

Identification of first and second-order phase transitions.

Discovery of bistability and spin squeezing regions.

Analysis of altered spin pumping dynamics.

Abstract

We investigate dissipative phase transitions in an open central spin system. In our model the central spin interacts coherently with the surrounding many-particle spin environment and is subject to coherent driving and dissipation. We develop analytical tools based on a self-consistent Holstein-Primakoff approximation that enable us to determine the complete phase diagram associated with the steady states of this system. It includes first and second-order phase transitions, as well as regions of bistability, spin squeezing and altered spin pumping dynamics. Prospects of observing these phenomena in systems such as electron spins in quantum dots or NV centers coupled to lattice nuclear spins are briefly discussed.