3:30–4:30 pm
Zoom Zoom link will be emailed to our events mailing list. To be added to this this, send your request to Tiffany Kurns<tkurns@uchicago.edu>
Dynamical phase transitions at many-body exceptional points
Peter Littlewood and Vincenzo Vitelli, University of Chicago
Spontaneous synchronization is at the core of many natural phenomena. Your heartbeat is maintained because cells contract in a synchronous wave; some bird species synchronize their motion into flocks; quantum synchronization is responsible for laser action and superconductivity. The transition to synchrony, or between states of different patterns of synchrony, is a dynamical phase transition that has much in common with conventional phase transitions of state – for example solid to liquid, or magnetism – but the striking feature of driven dynamical systems is that the components are “active”. Consequently quantum systems with dissipation and decay are described by non-Hermitian Hamiltonians, and active matter can abandon Newton’s third law and have non-reciprocal interactions. This substantially changes the character of many-degree-of-freedom dynamical phase transitions, and the critical phenomena in their vicinity, since the critical point is an “exceptional point” where eigenvalues coalesce.
We will illustrate this in two very different systems – a Bose-Einstein condensate of polaritons, and flocking of birds.
