Observation of Floquet band topology change in driven ultracold Fermi gases

Abstract

Periodic driving of a quantum system can significantly alter its energy bands and even change the band topology, opening a completely new avenue for engineering novel quantum matter. Although important progress has been made recently in measuring topological properties of Floquet bands in different systems, direct experimental measurement of Floquet band dispersions and their topology change is still demanding. Here we directly measure Floquet band dispersions in a periodically driven spin-orbit coupled ultracold Fermi gas. Using spin injection radio-frequency spectroscopy, we observe that the Dirac point originating from two dimensional spin-orbit coupling can be manipulated to emerge at the lowest or highest two dressed bands by fast modulating Raman laser frequencies, demonstrating topological change of Floquet bands. Our work will provide a powerful tool for understanding fundamental Floquet physics as well as engineering exotic topological quantum matter.

6 pages, 5 figures

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Cited by in corpus (9)

• Tailoring quantum gases by Floquet engineering
• Effective Floquet Hamiltonian in the low-frequency regime
• Tunable Flux through a Synthetic Hall Tube of Neutral Fermions
• Quantum phases in spin-orbit-coupled Floquet spinor Bose gases
• Real-time simulation of light-driven spin chains on quantum computers
• Two-body bound state of ultracold Fermi atoms with two-dimensional spin-orbit coupling
• Phase diagram, band structure and density of states in two-dimensional attractive Fermi-Hubbard model with Rashba spin-orbit coupling
• Chiral Raman coupling for spin-orbit coupling in ultracold atomic gases
• Lattice dynamics in an emergent Zeeman lattice