Condensation energy and the mechanism of superconductivity

TL;DR

This paper discusses the challenges in defining condensation energy in high-temperature superconductors where mean-field theory may not apply, and explores the energy mechanisms behind the superconducting transition.

Contribution

It clarifies the conceptual issues in measuring condensation energy and debates the nature of energy changes during the transition, emphasizing the importance of the normal state's anomalous properties.

Findings

Condensation energy is difficult to define without mean-field theory.

The nature of the energy driving the transition (kinetic vs potential) is largely semantic.

Normal state anomalies complicate quantitative analyses of superconductivity.

Abstract

Condensation energy in a superconductor cannot be precisely defined if mean-field theory fails to hold. This implies that in the case of high temperature superconductors, discussions of quantitative measures of condensation energy must be scrutinized carefully, because the normal state is anomalous and the applicability of a mean-field description can be questioned. A related issue discussed here is the precise meaning of a superconducting transition driven by kinetic as opposed to one driven by potential energy; we argue that this is a semantic question.