Abstract

Recent breakthroughs in the development of digital quantum devices promise to grant computational capacities far beyond the reach of classical architectures, and open unprecedented possibilities to study quantum many-body systems. This swift progress is fueling intense interest in the complex interplay of unitary quantum dynamics and non-unitary processes arising naturally in experiments, such as dissipation stemming from coupling to the environment or projective measurements performed on the system. This talk illustrates the rich dynamical phase diagrams that can emerge in these non-unitary settings. In the first part, we address the challenges of protecting quantum coherence against environmental noise, and explore the dynamical phase diagram of dissipative quantum many-body systems. In contrast to the general expectation that in an open system coherent information is quickly lost to the dissipative environment, we construct a regime of open quantum dynamics, functioning as a quantum error-correcting code which is dynamically protected against generic boundary noise. We comment on the implications of these results for designing robust quantum devices. We then turn to the effects of local measurements performed on the system. Specifically, we demonstrate that appropriately chosen projective measurements can imprint highly non-trivial order on quantum many-body systems, realizing the out-of-equilibrium counterpart of spontaneous symmetry breaking and symmetry protected topological order.