Pairing-gap, pseudo-gap, and no-gap phases in the radio-frequency spectra of a trapped unitary 6Li gas

TL;DR

This paper analyzes radio-frequency spectra of a trapped unitary 6Li gas, revealing the coexistence of pairing-gap, pseudo-gap, and no-gap phases across the critical temperature, thus clarifying previous interpretative puzzles.

Contribution

It introduces a theoretical approach that accounts for trap and final-state effects, elucidating phase distinctions in rf spectra of 6Li gases.

Findings

Identification of two main peaks associated with different phases

Observation of phase evolution across the critical temperature

Resolution of longstanding interpretative puzzle in rf spectra

Abstract

Radio frequency spectra of a trapped unitary 6Li gas are reported and analyzed in terms of a theoretical approach that includes both final-state and trap effects. Final-state effects play a crucial role in evidencing two main peaks both above and below the critical temperature Tc as being associated with two distinct phases that reside in different trap regions. These are the pairing-gap and pseudo-gap phases below Tc, which evolve into the pseudo-gap and no-gap phases above Tc. In this way, a long standing puzzle about the interpretation of rf spectra for 6Li in a trap is solved.