https://doi.org/10.1140/epja/s10050-022-00738-2
Regular Article - Theoretical Physics
Many-body approximations to the superfluid gap and critical temperature in pure neutron matter
1
TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada
2
Departament de Física Quàntica i Astrofísica, Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, Martí Franquès 1, 08028, Barcelona, Spain
3
Department of Physics, University of Surrey, GU2 7XH, Guildford, UK
Received:
15
February
2022
Accepted:
21
April
2022
Published online:
12
May
2022
We compute singlet pairing gaps and critical temperatures in pure neutron matter with different many-body approximations. Medium effects tend to reduce gaps and critical temperatures compared to the standard BCS ansatz. In the mean-field approximation, the ratio of these two quantities remains constant across a wide range of densities. This constant ratio is close to the universal prediction of BCS theory, whether three-neutron interactions are included or not. Using a more sophisticated many-body approach that incorporates the effect of short-range correlations in pairing properties, we find that the gap to critical temperature ratio in the low-density regime is substantially larger than the BCS prediction, independently of the interaction. In this region, our results are relatively close to experiments and theoretical calculations from the unitary Fermi gas. We also find evidence for a different density dependence of zero-temperature gaps and critical temperatures in neutron matter.
© The Author(s) 2022
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