University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Wednesday, November 6th 2019
1:25 pm:
Speaker:  Gregory Fiete, Northeastern University
Subject:  Effective Descriptions of Time Periodic Systems

Recently, there has been much interest in non-equilibrium phenomena in cold atomic gases and condensed matter systems. An important class of non-equilibrium systems includes those subjected to periodic drive, such as cold atoms in an optical lattice with periodically modulated parameters, or a solid state system with an incident laser beam. In this talk, I will describe some of our recent theoretical work aimed at finding accurate effective Hamiltonians for general periodically driven systems, including those with interactions. I will describe a “flow equation approach” inspired by renormalization group-type ideas that provides a useful description for highly accurate effective Hamiltonians. The method also serves as an anchor point for a wide range of approximate, physically motivated treatments of obtaining the effective Hamiltonian. I will also describe complementary work aimed at finding accurate Floquet Hamiltonians in the low-frequency, low-drive intensity limit.

References:

[1] M. Vogl, P. Laurell, A. D. Barr, G. A. Fiete, “A flow equation approach to periodically driven systems”, Phys. Rev. X 9, 021037 (2019).

[2] M. Vogl, P. Laurell, A. D. Barr, G. A. Fiete, “Analogue of Hamilton-Jacobi theory for the time-evolution operator”, Phys. Rev. A 100, 012132 (2019)

[3] M. Vogl, M. Rodriguez-Vega, G. A. Fiete, “Effective Floquet Hamiltonian in the low-frequency regime”, arXiv:09

Faculty Host: Natalia Perkins

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