Joint Seminar on Quantum Information and Technologies

The evolution of an isolated quantum system inevitably exhibits recurrence: the state returns to within epsilon of its initial condition after finite time. We establish first rigorous, tight and universal upper bounds on the recurrence time, depending on epsilon, system dimension and exit time (time to first leave the neighborhood of identity). For pure states evolving under a Hamiltonian H, estimating the exit time is equivalent to an inverse quantum speed limit problem, which we also solve. Joint work with Michał Oszmaniec.