Structure of the vacuum states in the presence of isovector and isoscalar pairing correlations

The long standing problem of proton-neutron pairing and, in particular, the limitations imposed on the solutions by the available symmetries, is revisited. We look for solutions with nonvanishing expectation values of the proton Δ<sub>p</sub>, the neutron Δ<sub>n</sub>, and t...

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Autores principales: Bes, D. R., Civitarese, Enrique Osvaldo, Maqueda, E. E., Scoccola, Norberto Nerio
Formato: Articulo
Lenguaje:Inglés
Publicado: 2000
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/126234
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Sumario:The long standing problem of proton-neutron pairing and, in particular, the limitations imposed on the solutions by the available symmetries, is revisited. We look for solutions with nonvanishing expectation values of the proton Δ<sub>p</sub>, the neutron Δ<sub>n</sub>, and the isoscalar Δ<sub>0</sub> gaps. For an equal number of protons and neutrons we find two solutions with Δ<sub>p</sub> = ± Δ<sub>n</sub>, respectively. The behavior and structure of these solutions differ for spin saturated (single l shell) and spin unsaturared systems (single j shell). In the former case the BCS results are checked against an exact calculation.