Detecting chiral pairing and topological superfluidity using circular dichroism

Abstract

Realising and probing topological superfluids is a key goal for fundamental science, with exciting technological promises. Here, we show that chiral $p_x+i{p}_y$ pairing in a two-dimensional topological superfluid can be detected through circular dichroism, namely, as a difference in the excitation rates induced by a clockwise and counter-clockwise circular drive. For weak pairing, this difference is to a very good approximation determined by the Chern number of the superfluid, whereas there is a non-topological contribution scaling as the superfluid gap squared that becomes signifiant for stronger pairing. This gives rise to a competition between the experimentally driven goal to maximise the critical temperature of the superfluid, and observing a signal given by the underlying topology. Using a combination of strong coupling Eliashberg and Berezinskii-Kosterlitz-Thouless theory, we analyse this tension for an atomic Bose-Fermi gas, which represents a promising platform for realising a chiral superfluid. We identify a wide range of system parameters where both the critical temperature is high and the topological contribution to the dichroic signal is dominant.

6 pages, 3 figures

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Cited by in corpus (6)

• Signatures of two- and three-dimensional semimetals from circular dichroism
• Topological transport of mobile impurities
• Intrinsic Anomalous Hall Effect in a Bosonic Chiral Superfluid
• Relating the Hall conductivity to the many-body Chern number using Fermi's Golden rule and Kramers-Kronig relations
• Anomalous Hall effect in single-band chiral superconductors from impurity superlattices
• Intrinsic anomalous Hall effect across the magnetic phase transition of a spin-orbit-coupled Bose-Einstein condensate