Spin-polarized neutron matter: Critical unpairing and BCS-BEC precursor
| Autor: | Stein, Martin, Sedrakian, Armen, Huang, Xu-Guang, Clark, John W. |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Phys. Rev. C 93, 015802 (2016) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevC.93.015802 |
| Popis: | We obtain the critical magnetic field required for complete destruction of $S$-wave pairing in neutron matter, thereby setting limits on the pairing and superfluidity of neutrons in the crust and outer core of magnetars. We find that for fields $B \ge 10^{17}$ G the neutron fluid is non-superfluid -- if weaker spin-1 superfluidity does not intervene -- a result with profound consequences for the thermal, rotational, and oscillatory behavior of magnetars. Because the dineutron is not bound in vacuum, cold dilute neutron matter cannot exhibit a proper BCS-BEC crossover. Nevertheless, owing to the strongly resonant behavior of the $nn$ interaction at low densities, neutron matter shows a precursor of the BEC state, as manifested in Cooper-pair correlation lengths {being} comparable to the interparticle distance. We make a systematic quantitative study of this type of BCS-BEC crossover in the presence of neutron fluid spin-polarization induced by an ultra-strong magnetic field. We evaluate the Cooper pair wave-function, quasiparticle occupation numbers, and quasiparticle spectra for densities and temperatures spanning the BCS-BEC crossover region. The phase diagram of spin-polarized neutron matter is constructed and explored at different polarizations. Comment: 13 RevTex pages, 18 figures, v2: minor changes, references added, matches published version |
| Databáze: | arXiv |
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