IMSc Webinar

New Forms of Ergodicity Breaking in Quantum Many-Body Systems

Sanjay Moudgalya, California Institute of Technology (CalTech)

A cornerstone in the dynamics of isolated quantum systems is the Eigenstate Thermalization Hypothesis (ETH), which provides a sufficient
condition for the thermalization of initial states under time-evolution by a quantum Hamiltonian. Eigenstates of nonintegrable
Hamiltonians were believed to always satisfy ETH in the absence of an extensive number of conserved quantities. However, recent results
suggest that this is not always the case. In this talk, I will discuss two recently discovered mechanisms of ergodicity breaking:
Quantum Scars and Hilbert Space Fragmentation. In both these cases, ETH-violating eigenstates coexist with ETH-satisfying ones, and the
fate of an initial state under time evolution depends on the properties of eigenstates it has weights on, thus revealing the breaking of
ergodicity. I will further discuss examples of multiple physically relevant systems that exhibit similar phenomenology and discuss their
dynamics.

Link to the Google meet:
meet.google.com/xzy-pnxo-njt