FYI (First appeared on arXiv in May, 2017):
"The nature of the normal phase of strongly correlated fermionic systems is an
outstanding question in quantum many-body physics. We use spatially resolved
radio-frequency spectroscopy to measure pairing energy of fermions across a
wide range of temperatures and interaction strengths in a two-dimensional gas
of ultracold fermionic atoms. We observe many-body pairing at temperatures far
above the critical temperature for superfluidity. In the strongly interacting
regime, the pairing energy in the normal phase significantly exceeds the
intrinsic two-body binding energy of the system and shows a clear dependence on
local density. This implies that pairing in this regime is driven by many-body
correlations, rather than two-body physics. Our findings show that pairing
correlations in strongly interacting two-dimensional fermionic systems are
remarkably robust against thermal fluctuations."
Some excerpts from/following above links:
"We perform our experiments with a two-component mixture of 6Li atoms with
approximately 3 × 104 particles per spin state that are loaded into a single
layer of an anisotropic harmonic optical trap."
"Using a technique known as radio-frequency spectroscopy, the researchers
measured the response of the atoms to a radio-wave pulse. From this response,
they could tell exactly whether or not the particles were paired and in what
"Beyond this previously explored regime, our measurements reveal that many-body
effects enhance the pairing energy far above the critical temperature, with the
maximum enhancement occurring at ln(kFa2D) ≈ 1, where a reliable mean-field
description is not available."