Superradiant phase transition with cavity assisted dynamical spin-orbit coupling

TL;DR

This paper investigates the superradiant phase transition in a system with cavity-assisted dynamical spin-orbit coupling, revealing unique quantum phenomena and effects of decay and nonlinearities on the phase diagram.

Contribution

It introduces a theoretical framework for analyzing superradiant phase transitions with cavity-assisted dynamical spin-orbit coupling, highlighting novel quantum effects.

Findings

Discovery of flat spectrum and excitation energy singularity near critical point

Atom decay suppresses spectral singularities

Nonlinear coupling breaks phase transition symmetry

Abstract

Superradiant phase transition represents an important quantum phenomenon that shows the collective excitations based on the coupling between atoms and cavity modes. The spin-orbit coupling is another quantum effect which induced from the interaction of the atom internal degrees of freedom and momentum of center-of-mass. In this work, we consider the cavity assisted dynamical spin-orbit coupling which comes from the combination of these two effects. It can induce a series of interesting quantum phenomena, such as the flat spectrum and the singularity of the excitation energy spectrum around the critical point of quantum phase transition. We further discuss the influence of atom decay and nonlinear coupling to the phase diagram. The atom decay suppresses the singularity of the phase diagram and the nonlinear coupling can break the symmetric properties of the phase transition. Our work provide the theoretical methods to research the rich quantum phenomena in this dynamic many-body systems.