Emergence of hydrodynamics in large driven quantum systems

ORAL

Abstract

Many non-equilibrium dynamical properties of Floquet (driven) systems remain unclear. In particular, understanding the microscopic details of short-time thermalization as well as the cross-over to hydrodynamics and late-time Floquet heating remains an open challenge. We investigate the dynamics of Floquet systems using a novel numerical method termed 'density matrix truncation' (DMT). At small system sizes, we gauge the applicability and limitations of DMT via comparison with Krylov subspace methods; we demonstrate that DMT can capture both the prethermal state and the late-time thermalization to infinite temperature. Pushing DMT to larger system sizes (up to L = 100) enables us to confirm the exponential scaling of the Floquet heating time with driving frequency. Access to large systems allows us to directly study the emergence of late-time hydrodynamics. In particular, we implement a spatially inhomogeneous drive to probe the interplay between Floquet heating and the diffusion of local energy density. Despite the heating being a coherent quantum process, the emergent hydrodynamical behavior is captured by a simple classical diffusion equation.

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Presenters

  • Bingtian Ye

    Department of Physics, University of California, Berkeley

Authors

  • Bingtian Ye

    Department of Physics, University of California, Berkeley

  • Francisco Machado

    University of California, Berkeley, Physics, University of California, Berkeley, Department of Physics, University of California, Berkeley

  • Christopher White

    Institute for Quantum Information and Matter, Caltech

  • Roger Mong

    Physics, University of Pittsburgh, Physics and Astronomy, University of Pittsburgh, University of Pittsburgh, Department of Physics and Astronomy, University of Pittsburgh

  • Norman Yao

    University of California, Berkeley, Department of Physics, University of California, Berkeley, California 94720, USA, Physics, University of California, Berkeley, Department of Physics, University of California, Berkeley, University of California, Berkeley and Lawrence Berkeley National Laboratory, Materials Sciences Division