Realizing a one-dimensional topological gauge theory in an optically dressed Bose-Einstein condensate
Speaker: Leticia Tarruell, ICFO-The Institute of Photonic Sciences, Castelldefels (Barcelona), Spain
Date and time: Wednesday, 1 December 2021, 14:00 Vilnius time
Location: MSTeams meeting (link below)
Quantum gases constitute a versatile testbed for exploring the behaviour of quantum matter subjected to electric and magnetic fields. While most experiments consider classical gauge fields that act as a simple static background for the atoms, gauge fields appearing in nature are instead quantum dynamical entities that are influenced by the spatial configuration and motion of matter, and that fulfil local symmetry constraints. In my talk, I will discuss our recent realization of a chiral BF theory: a topological gauge theory for linear anyons that corresponds to a possible one-dimensional reduction of the Chern-Simons gauge theory effectively describing fractional quantum Hall systems [1-3]. By using the local symmetry constraint of the theory, we encode the gauge field in terms of the matter field. The result is a system with chiral interactions, which we engineer in a potassium Bose-Einstein condensate by synthesizing optically dressed atomic states with a momentum-dependent scattering length. When this dependence is linear, matter behaves as if minimally coupled to a density-dependent vector potential. Theoretically, we show that the system then realizes the chiral BF Hamiltonian at the quantum level. Experimentally, we observe its two main features: the formation of chiral bright solitons - self-bound states of the matter field that only exist when propagating in one direction – and the back-action of matter into the gauge field. Our results establish chiral interactions as a novel resource for quantum simulation experiments with ultracold atoms and pave the way towards implementing topological gauge theories in higher dimensions .
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MSTeams link: https://teams.microsoft.com/l/channel/19%3a95ac9712144e4ab6b0c1040404c7dc84%40thread.tacv2/General?groupId=2feb718a-6943-4d00-98f4-c39354a50253&tenantId=82c51a82-548d-43ca-bcf9-bf4b7eb1d012