Exact multistability and dissipative time crystals in interacting fermionic lattices

Abstract The existence of multistability in quantum systems beyond the mean-field approximation remains an intensely debated open question. Quantum fluctuations are finite-size corrections to as full exact solution is unobtainable and they usually destroy present on level. Here, by identifying using modulated dynamical symmetries a driven-dissipative fermionic chain we exactly prove presence fluctuations. Further, unlike common cases our model, rather than destroying multistability, themselves exhibit which absent level for systems. Moreover, studied model acquires additional thermodynamic that imply persistent periodic oscillations, constituting first case boundary time crystal,to best knowledge, genuine extended many-body system with previous being only emergent single- or few-body models. can be made into dissipative crystal limit large dissipation (i.e. oscillations stabilized dissipation) making it both crystal.