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arXiv · 1307.2701

Coherence Factors Beyond the BCS Result

Gregory Gorohovsky·Eldad Bettelheim
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Abstract

The dynamics of BCS (Bardeen-Cooper-Schrieffer) superconductors is fairly well understood due to the availability of a mean field solution for the pairing Hamiltonian, a solution which gives the quantum state of superconductor as a state of almost-free fermions interacting only with a condensate. As a result, transition probabilities may be computed, and expressed in terms of matrix elements of electron creation and annihilation operators between approximate eigenstates. These matrix elements are also called 'coherent factors'. Mean-field theory is however not sufficient to describe all eigenstates of a superconductor, a deficiency which is hardly important in (or very close) to equilibrium, but one that becomes relevant in certain out of equilibrium situations. We report here on a computation of matrix elements (coherence factors) for the pairing Hamiltonian between any 'two-arc' eigenstates in the thermodynamic limit.

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Gregory Gorohovsky, Eldad Bettelheim. 2013-07-10. Coherence Factors Beyond the BCS Result. https://doi.org/10.1103/physrevb.88.060510

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