Семинар международной лаборатории физики конденсированного состояния: Ilya A. Gruzberg (Ohio State University) "Low-frequency conductivity of disordered wires: integrability and instantons"
В среду 24 мая 2017г. в 15:00
состоится научный семинар Международной лаборатории физики конденсированного состояния
Ilya A. Gruzberg (Ohio State University)
Low-frequency conductivity of disordered wires:
integrability and instantons
Generic states of non-interacting electrons in disordered wires are localized, and the DC conductivity of a wire vanishes at zero temperature. However, the AC conductivity is non-vanishing, and its general asymptotic form at low frequency was obtained by Mott who used intuitive qualitative arguments. Then this formula was rigorously derived by Berezinsky for a strictly one-dimensional (1D) disordered system. Later Hayn and John have re-derived the Mott-Berezinsky formula applying instanton techniques to localized states in the Lifshits tails (at large negative energies). We revisit the instanton approach and apply it to the statistics of wave functions and AC transport, calculating exactly the integral over gaussian fluctuations around the exact two-instanton solution. We demonstrate that quite generically the contribution of zero modes to the fluctuation determinant exactly cancels the Jacobian that appears when the collective variable are introduced. Thus, we derive the correlations between eigenfunctions at different energies beyond the leading order in small energy difference. This allows us to calculate the leading corrections to the Mott-Berezinsky law. We also extend this approach to quasi-1D wires.
ул.Ст.Басманная, 21/4, стр. 5, ауд.Б-312.
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