On the "non-perturbative analysis" of zero-temperature dephasing: I. Dyson equation and self energy

TL;DR

This paper critically examines a proposed non-perturbative analysis of zero-temperature dephasing, highlighting inconsistencies in the suggested self-energy structure with its fundamental definition.

Contribution

It challenges the validity of a recent non-perturbative approach to zero-temperature dephasing by analyzing the self-energy's structure.

Findings

The proposed self-energy structure is incompatible with its fundamental definition.

The critique questions the mathematical basis of the non-perturbative analysis.

The paper clarifies the correct conceptual framework for self-energy in this context.

Abstract

We point out that the structure of the self-energy suggested in cond-mat/0208140 as a result of a ``non-perturbative analysis'' by ``purely mathematical means'' is incompatible with the very definition of the self-energy.