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Updated: Jul 26, 2026

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures
Published on: October 9, 2012
Beyond linear response spectroscopy of ultracold fermi gases
1Department of Physics, Nanoscience Center, University of Jyväskylä, P.O. Box 35, FIN-40014, Finland.
Abstract:
We study rf spectroscopy of ultracold Fermi gas by going beyond the linear response in the field-matter interaction. Higher order perturbation theory allows virtual processes and energy conservation beyond the single-particle level. We formulate an effective higher order theory, which agrees quantitatively with experiments on the pairing gap and is consistent with the absence of the mean-field shift in the spin-flip experiment.
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