Research

Mixed-state phases

Physical systems are never in isolation. We investigate many-body physics in open quantum systems and have uncovered new physical phenomena, such as a new type of spontaneous symmetry breaking, and topological phases that can only appear in open systems. We have also discovered quantum topological order at finite temperature in three dimensions.

Defects and extended operators

Extended operators probe quantum many-body systems in ways local observables cannot. We study disorder operators, which measure the symmetry charge in a spatial region, and Rényi entanglement entropies of subsystems — both realized as defects in spacetime. Their scaling behavior reveals new universal quantities characterizing global structures of quantum states, in topological phases, quantum critical points and thermal states.

Symmetry and anomaly in topological phases

Under construction.

Fractonic phases

Under construction.