Comment on `Evidence for pairing above Tc from the dispersion in the pseudogap phase of cuprates' by A. Kanigel et al

TL;DR

This paper discusses the theoretical prediction and experimental evidence of Bogoliubov-type excitations in the pseudogap phase of cuprates, highlighting the role of phase-correlated bosonic pair fluctuations above Tc.

Contribution

It provides a theoretical framework predicting Bogoliubov modes in the pseudogap phase, aligning with recent experimental observations by Kanigel et al.

Findings

Experimental evidence of Bogoliubov excitations in pseudogap phase

Theoretical prediction of propagating bosonic pair fluctuations above Tc

Reflection of pseudogap features in single particle excitations

Abstract

In a recent preprint [0803.3052] A. Kanigel et al report evidence for Bogoliubov-type excitations in the pseudogap phase in the anti-nodal region, where a robust pseudogap remains well above Tc. This important experimental result has been theoretically predicted by us almost 6 years ago on a basis of the phenomenological boson fermion model. An earlier theoretical prediction on the basis of this model was that of a pseudogap in the electron DOS, setting in at some temperature T* and evolving into the superconducting gap upon approaching Tc. A natural logical pursuit of this early work was to show that, in order to have a superconducting state evolved out of a pseudogap state, the diamagnetic bosonic pair fluctuations (characterizing the pseudogap phase) have to be propagating modes, which are phase correlated over finite distances above Tc. If so, then the pseudogap feature has to be reflected in characteristic features of the single particle excitations, showing remnants of the Bogoliubov modes inherent in the superconducting phase. Such Bogoliubov modes result from dynamical feedback effects between single electron excitations and dynamical local pairing fluctuations. We briefly recollect here our theoretical results and confront them with the recent experimental findings.