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arXiv · 1807.04915

Spinor self-ordering of a quantum gas in a cavity

Ronen M. Kroeze·Yudan Guo·Varun D. Vaidya·Jonathan Keeling·Benjamin L. Lev
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Abstract

We observe the joint spin-spatial (spinor) self-organization of a two-component BEC strongly coupled to an optical cavity. This unusual nonequilibrium Hepp-Lieb-Dicke phase transition is driven by an off-resonant two-photon Raman transition formed from a classical pump field and the emergent quantum dynamical cavity field. This mediates a spinor-spinor interaction that, above a critical strength, simultaneously organizes opposite spinor states of the BEC on opposite checkerboard configurations of an emergent 2D lattice. The resulting spinor density-wave polariton condensate is observed by directly detecting the atomic spin and momentum state and by holographically reconstructing the phase of the emitted cavity field. The latter provides a direct measure of the spin state, and a spin-spatial domain wall is observed. The photon-mediated spin interactions demonstrated here may be engineered to create dynamical gauge fields and quantum spin glasses.

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Ronen M. Kroeze, Yudan Guo, Varun D. Vaidya, Jonathan Keeling, Benjamin L. Lev. 2018-07-13. Spinor self-ordering of a quantum gas in a cavity. https://doi.org/10.1103/physrevlett.121.163601

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