Kanász-Nagy, M.Glazman, L.Esslinger, T.Demler, E. A.2019-09-262016Kanász-Nagy, M., L. Glazman, T. Esslinger, and E. A. Demler. 2016. “Anomalous Conductances in an Ultracold Quantum Wire.” Physical Review Letters 117 (25). https://doi.org/10.1103/physrevlett.117.255302.0031-90071079-71141092-0145http://nrs.harvard.edu/urn-3:HUL.InstRepos:41412219We analyze the recently measured anomalous transport properties of an ultracold gas through a ballistic constriction [S. Krinner et al., Proc. Natl. Acad. Sci. U. S. A. 113, 8144 (2016)]. The quantized conductance observed at weak interactions increases severalfold as the gas is made strongly interacting, which cannot be explained by the Landauer theory of single-channel transport. We show that this phenomenon is due to the multichannel Andreev reflections at the edges of the constriction, where the interaction and confinement result in a superconducting state. Andreev processes convert atoms of otherwise reflecting channels into the condensate propagating through the constriction, leading to a significant excess conductance. Furthermore, we find the spin conductance being suppressed by superconductivity; the agreement with experiment provides an additional support for our model.en-USJournal Article2019-09-2610.1103/PhysRevLett.117.255302