Pion-mediated Cooper pairing of neutrons: beyond the bare vertex approximation
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Published:2023-07-11
Issue:8
Volume:50
Page:085101
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ISSN:0954-3899
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Container-title:Journal of Physics G: Nuclear and Particle Physics
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language:
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Short-container-title:J. Phys. G: Nucl. Part. Phys.
Author:
Zhu Hao-FuORCID,
Liu Guo-ZhuORCID
Abstract
Abstract
In some quantum many particle systems, the fermions could form Cooper pairs by exchanging intermediate bosons. This then drives a superconducting phase transition or a superfluid transition. Such transitions should be theoretically investigated by using proper non-perturbative methods. Here we take the neutron superfluid transition as an example and study the Cooper pairing of neutrons mediated by neutral π-mesons in the low-density region of a neutron matter. We perform a non-perturbative analysis of the neutron–meson coupling and compute the pairing gap Δ, the critical density ρ
c
, and the critical temperature T
c
by solving the Dyson–Schwinger equation of the neutron propagator. We first carry out calculations under the widely used bare vertex approximation and then incorporate the contribution of the lowest-order vertex correction. This vertex correction is not negligible even at low densities and its importance is further enhanced as the density increases. The transition critical line on density-temperature plane obtained under the bare vertex approximation is substantially changed after including the vertex correction. These results indicate that the vertex corrections play a significant role and need to be seriously taken into account.
Funder
National Natural Science Foundation of China
Subject
Nuclear and High Energy Physics