2020/10/31 by David Durel, Michael Urban · 8 citations
Physics and Astronomy · #Atomic and Subatomic Physics Research #Cold Atom Physics and Bose-Einstein Condensates #Crossover #Neutron #Neutron scattering #Nuclear matter #Phase (matter) #Pseudogap #Pulsars and Gravitational Waves Research #Quasiparticle #Scattering #Ultracold neutrons #cond-mat.quant-gas #nucl-th
paper · pdf · doi:10.3390/universe6110208
published in Universe 6(11), 208 (Multidisciplinary Digital Publishing Institute) · 16 pages; v2: minor changes, references added
openalex created_date 2020/10/15 · arxiv created 2020/11/12 · openalex publication_date 2020/11/13 · arxiv updated 2020/11/16 · openalex updated_date 2026/08/05
Due to the large neutron–neutron scattering length, dilute neutron matter resembles the unitary Fermi gas, which lies half-way in the crossover from the BCS phase of weakly coupled Cooper pairs to the Bose–Einstein condensate of dimers. We discuss crossover effects in analogy with the T-matrix theory used in the physics of ultracold atoms, which we generalize to the case of a non-separable finite-range interaction. A problem of the standard Nozières–Schmitt-Rink approach and different ways to solve it are discussed. It is shown that in the strong-coupling regime, the spectral function exhibits a pseudo-gap at temperatures above the critical temperature Tc. The effect of the correlated density on the density dependence of Tc is found to be rather weak, but a possibly important effect due to the reduced quasiparticle weight is identified.