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Dresden 2003 – scientific programme

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SYQD: Quantum decoherence in solid state physics

SYQD 1: Quantum Decoherence in Solid State Physics I

SYQD 1.6: Invited Talk

Tuesday, March 25, 2003, 16:30–17:00, HSZ/01

Decoherence of Interacting Electrons in Disordered Conductors: on the Relation between Influence Functional and diagrammatic approaches — •Jan von Delft — Sektion Physik und Center for NanoScience der Ludwig-Maximilians-Universität München, 80333, München, Germany

A few years ago, Golubev and Zaikin (GZ) developed an influence functional approach (reviewed in [1]) for describing interacting fermions in a disordered conductor: the diffusive motion of an electron interacting with its environment (other electrons) is captured in an effective action i SR + SI, which in principle correctly accounts for the Pauli principle (via SR). GZ used their approach to calculate the electron decoherence time τφ(T), and found it to be finite at zero temperature: τφ(T → 0) = τϕ0. This contradicts the standard view, based on the work of Altshuler, Aronov and Khmelnitskii, that τφ(T → 0)= ∞. In this talk, I shall review the various recent (and controversial [2]) calculations of τφ. I conclude [3] that
(i) GZ’s influence functional is in principle consistent with standard Keldysh diagrammatic perturbation theory; but
(ii) when applying their influence functional, GZ obtain a finite τφ0 because they make a semiclassically-motivated approximation which violates the Pauli principle (concretely, they claim that SR can be neglected when calculating τφ0). I argue that this approximation breaks down at low temperatures.

[1] D. S. Golubev, A. D. Zaikin, and G. Schön, cond-mat/0110495.

[2] Aleiner et al., cond-mat/9808053, cond-mat/0110545.

[3] Jan von Delft, cond-mat/0210644.

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