1 research outputs found
The non-reciprocal Dicke model
We investigate the physics of an open two-component Dicke model, where the
light field mediates non-reciprocal interactions between two spin species. We
show that the model, which we dub non-reciprocal Dicke model, exhibits a
discrete parity-time () symmetry and we characterize the
emergence of a non-stationary phase, so far explained in terms of
dissipation-induced instability, as spontaneous breaking of
symmetry. We further show that such symmetry breaking embodies
an instance of a non-reciprocal phase transition, a concept recently introduced
by Fruchart [Nature , 363 (2021)]. Remarkably, the phase
transition in our model does not necessitate the presence of any underlying
broken symmetry or exceptional points in the spectrum, both believed to be
essential requirements for non-reciprocal phase transitions. Our results
establish driven-dissipative light-matter systems as a new avenue for exploring
non-reciprocal phase transitions and contribute to the theory of non-reciprocal
collective phenomena.Comment: 5+3 pages, 4+2 figure