2025/07/29 by Kuklov, Anatoly, Radzihovsky, Leo, Svistunov, Boris
#FOS: Physical sciences #Quantum Gases (cond-mat.quant-gas) #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2507.21766
We introduce a class of dynamical field theories for N-component "Borromean" (N≥ 3) super-counterfluid order, naturally formulated in terms of inter-species bosonic fields ψαβ. Their condensation breaks the normal-state [U(1)]N symmetry down to its diagonal U(1) subgroup, thereby encoding the arrest of the net superflow. This approach broadens our understanding of dynamical properties of super-counterfluids, at low energies capturing its universal properties, phase transition, counterflow vortices, and many of its other properties. Such super-counterfluid strikingly exhibits N distinct flavors of energetically stable elementary vortex solutions, despite ℤN-1 homotopy group of its N - 1 independent Goldstone modes, with N - 1 topologically distinct elementary vortex types, obeying modular arithmetic. The model leads to Borromean hydrodynamics as a low-energy theory, reveals counteflow AC Josephson effect, and generically predicts a first-order character of the phase transitions into Borromean super-counterfluid state in dimensions greater than two.