Théorique, numérique
Unitarity is a fundamental property of quantum mechanics which underlies the dynamics of closed quantum many-body systems, the concept of thermalisation and the emergence of statistical mechanics. A different paradigm for quantum dynamics arises in presence of an external environment, which can represent for example dissipation due to a bath or an external monitoring apparatus. Other sources of non-unitarity can arise for example in presence of non-Hermiticity due to post-selection of measurement outcomes or to non-reciprocal, “one-way” interactions, the latter providing a novel paradigm for phase transitions in active matter and finding several applications in quantum information processing. The goal of this project is to explore the consequences of non-unitarity on the dynamics of quantum many-body systems, in particular for what concerns the dynamics of quantum information. Examples include: the study of entanglement dynamics in presence of non-reciprocal couplings, the role of interactions in simple models of monitored quantum systems or the robustness of measurement induced transitions to different types of measurement protocols and observables.