QM Seminar Speaker Daniil Antonenko (Landau Institute / Skoltech) Wednesday, March 4 pm in Le Conte 402

Host Vlad Kozii/Joel Moore
Time/Venue Tomorrow, Wednesday, March 4 pm in Le Conte 402
Title Mesoscopic conductance fluctuations in topological superconducting wires
Abstract We study quasiparticle transport in the bulk of disordered topological superconducting wires (length L) of symmetry class D, which can have a pair of edge Majorana states. Our focus is the critical regime between topological and critical phases, in which average conductance <g> scales as 1/\sqrt{L} at large L. We calculate conductance variance var g with the help of n = 2 (two-replica) nonlinear supersymmetric sigma-model, which boils down to the Fourier analysis on the sigma-model supermanifold. Eigenfunctions of the corresponding Laplace-Beltrami operator were constructed with the help of Iwasawa parametrisation. We obtained explicit expression for var g at arbitrary L in the diffusive regime, which describes the crossover from the regime of Drude conductivity at small lengths to the regime of a broad conductance distribution at large lengths. Also we analyse the case of left/right channels imbalance, which is described by a sigma-model with Wess-Zumino-Witten topological term.

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