Flow equation approach to the pairing problems

T. Domanski

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arXiv · cond-mat/0602236

Flow equation approach to the pairing problems

T. Domanski

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Abstract

We apply the flow equation method for studying the fermion systems where pairing interactions can either trigger the BCS instability with the symmetry breaking manifested by the off-diagonal order parameter or lead to the gaped single particle spectrum without any symmetry breaking. We construct the continuous Bogoliubov transformation in a scheme resembling the renormalization group procedure. We further extend this continuous transformation to a case where fermion pairs interact with the boson field. Due to temporal quantum fluctuations the single particle excitation spectrum develops a gap which is centered around the renormalized boson energy. When bosons undergo the Bose Einstein condensation this structure evolves into the BCS spectrum.

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T. Domanski. 2006-02-09. Flow equation approach to the pairing problems. https://arxiv.org/abs/cond-mat/0602236

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