A dissipative time crystal with or without ${\mathbb{Z}}_2$ symmetry breaking

We study an emergent semiclassical time crystal composed of two interacting driven-dissipative bosonic modes. The system has a discrete ${\mathbb{Z}}_2$ spatial symmetry which, depending on the strength of the drive, can be broken in the time-crystalline phase or it cannot. An exact semiclassical mean-field analysis, numerical simulations in the quantum regime, and the spectral analysis of the Liouvillian are combined to show the emergence of the time crystal and to prove the robustness of the oscillation period against quantum fluctuations.