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Renormalization of the electron-phonon interaction: a reformulation of the BCS-gap equation

A. Huebsch·K. W. Becker
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Abstract

A recently developed renormalization approach is used to study the electron-phonon coupling in many-electron systems. By starting from an Hamiltonian which includes a small gauge symmetry breaking field, we directly derive a BCS-like equation for the energy gap from the renormalization approach. The effective electron-electron interaction for Cooper pairs does not contain any singularities. Furthermore, it is found that phonon-induced particle-hole excitations only contribute to the attractive electron-electron interaction if their energy difference is smaller than the phonon energy.

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A. Huebsch, K. W. Becker. 2003-06-13. Renormalization of the electron-phonon interaction: a reformulation of the BCS-gap equation. https://doi.org/10.1140/epjb%2Fe2003-00180-9

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