Résumé |
A many-body quantum system that is continually monitored by an external
observer may be in distinct dynamical phases, distinguished by whether or not
the observers repeated local measurements prevent the build-up of long-range
quantum correlations. The universal properties of the measurement phase
transitions between these phases remain a challenge. I will describe
theoretical approaches to measurement transitions, making connections with
models in classical statistical mechanics such as percolation, disordered
magnets, and traveling waves. I will argue that exact results are possible in
some regimes, including for quantum circuits with all-to-all interactions. |