Anderson (de-)localization and quantum Sinai diffusion in disordered topological nanowires

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• Dmitry Bagrets (Cologne)
• Thursday 08 December 2016, 13:45-15:00
• Theory Library.

If you have a question about this talk, please contact Mike Gunn.

In my talk I discuss an analytic theory of quantum criticality in quasi one-dimensional topological Anderson insulators. I will show that these systems can be described in terms of two parameters – (thermal) conductance and the averaged over disorder topological index – representing localization and topological properties, respectively. Certain critical values of the average topological index (half-integer for Z classes, or zero for Z2 classes) define phase boundaries between distinct topological sectors. Upon increasing system size, the two parameters exhibit flow similar to the celebrated two parameter flow of the integer quantum Hall insulator. However, unlike the quantum Hall system, an exact analytical description of the entire phase diagram can be given in terms of the transfer-matrix solution of corresponding supersymmetric non-linear sigma-models. In Z2 classes one uncovers a hidden supersymmetry, present at the quantum critical point. In the end of the talk I will discuss the dynamical correlation function of diffusion modes close to criticality and relate it to the classical Sinai diffusion process. I will argue that such anomalously slow diffusion can be observed in class Z2 disordered Majorana wires in quench-like experiments.

This talk is part of the Theoretical Physics Seminars series.

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• Bham Talks
• Theoretical Physics Seminars
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