Peaks and widths of radio-frequency spectra: An analysis of the phase diagram of ultra-cold Fermi gases

Fuente: arXiv
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Autori principali: Pisani, L., Pini, M., Pieri, P., Strinati, G. Calvanese
Natura: Preprint
Pubblicazione: 2023
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author Pisani, L.
Pini, M.
Pieri, P.
Strinati, G. Calvanese
author_facet Pisani, L.
Pini, M.
Pieri, P.
Strinati, G. Calvanese
contents We provide a comprehensive theoretical study of the radio-frequency (rf) spectra of a two-component Fermi gas with balanced populations in the normal region of the temperature-vs-coupling phase diagram. In particular, rf spectra are analyzed in terms of two characteristic peaks, which can be either distinct or overlapping. On the BEC side of the crossover, these two contributions are associated with a fermionic quasi-particle peak and a bosonic-like contribution due to pairing. On the BCS side of the crossover, the two peaks are instead associated with interactions between particles occurring, respectively, at high or low relative momenta. Through this two-peak analysis, we show how and to what extent the correlation between the widths of the rf spectra and the pair size, previously identified in the superfluid phase at low temperature, can be extended to the normal phase, as well as how the temperature-vs-coupling phase diagram of the BCS-BEC crossover can be partitioned in a number of distinct physical sectors. Several analytic results for the shape and widths of the rf spectra are also derived in appropriate temperature and coupling limits.
format Preprint
id arxiv_https___arxiv_org_abs_2311_00479
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Peaks and widths of radio-frequency spectra: An analysis of the phase diagram of ultra-cold Fermi gases
Pisani, L.
Pini, M.
Pieri, P.
Strinati, G. Calvanese
Quantum Gases
Superconductivity
Quantum Physics
We provide a comprehensive theoretical study of the radio-frequency (rf) spectra of a two-component Fermi gas with balanced populations in the normal region of the temperature-vs-coupling phase diagram. In particular, rf spectra are analyzed in terms of two characteristic peaks, which can be either distinct or overlapping. On the BEC side of the crossover, these two contributions are associated with a fermionic quasi-particle peak and a bosonic-like contribution due to pairing. On the BCS side of the crossover, the two peaks are instead associated with interactions between particles occurring, respectively, at high or low relative momenta. Through this two-peak analysis, we show how and to what extent the correlation between the widths of the rf spectra and the pair size, previously identified in the superfluid phase at low temperature, can be extended to the normal phase, as well as how the temperature-vs-coupling phase diagram of the BCS-BEC crossover can be partitioned in a number of distinct physical sectors. Several analytic results for the shape and widths of the rf spectra are also derived in appropriate temperature and coupling limits.
title Peaks and widths of radio-frequency spectra: An analysis of the phase diagram of ultra-cold Fermi gases
topic Quantum Gases
Superconductivity
Quantum Physics
url https://arxiv.org/abs/2311.00479