A step for gauge fields in lattices and a twist by Dissipation ( Prof. Tilman Esslinger)

A step for gauge fields in lattices and a twist by Dissipation

  • Date: Nov 19, 2019
  • Time: 14:30
  • Speaker: Prof. Tilman Esslinger
  • ETH Zürich, Switzerland
  • Location: Max Planck Institute of Quantum Optics
  • Room: Herbert Walther Lecture Hall
The coupling between gauge and matter fields plays an important role in many models of high-energy and condensed matter physics. In these models, the gauge fields are dynamical quantum degrees of freedom in the sense that they are influenced by the spatial configuration and motion of the matter field. So far, synthetic magnetic fields for atoms in optical lattices were intrinsically classical, as these did not feature back-action from the atoms.

I will report on a scheme realizing the fundamental ingredient for a density-dependent gauge field by engineering non-trivial Peierls phases that depend on the site occupation of fermions in a Hubbard model. [F. Görg, K. Sandholzer, J. Minguzzi, R. Desbuquois, M. Messer, and T. Esslinger, Nat. Phys. https://doi.org/10.1038/s41567-019-0615-4(2019).].

Dissipative and unitary processes define the evolution of a many-body system. We discovered a non-stationary state of chiral nature in a synthetic many-body system with independently controllable unitary and dissipative couplings. Our experiment is based on a spinor Bose gas interacting with an optical resonator. Orthogonal quadratures of the resonator field coherently couple the Bose-Einstein condensate to two different atomic spatial modes whereas the dispersive effect of the resonator losses mediates a dissipative coupling between these modes. In a regime of dominant dissipative coupling we observe a chiral evolution with regimes reminiscent of limit cycles [N. Dogra, M. Landini, K. Kroeger, L. Hruby, T. Donner, and T. Esslinger, arXiv:1901.05974].

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