Article ID Journal Published Year Pages File Type
1840941 Nuclear Physics B 2012 35 Pages PDF
Abstract

We study integrable cases of pairing BCS hamiltonians containing several types of fermions. We prove that there exist three classes of such integrable models associated with classical rational r  -matrices and Lie algebras gl(2m)gl(2m), sp(2m)sp(2m) and so(2m)so(2m) correspondingly. We diagonalize the constructed hamiltonians by means of the algebraic Bethe ansatz. In the partial case of two types of fermions (m=2m=2) the obtained models may be interpreted as N=ZN=Z proton–neutron integrable models. In particular, in the case of sp(4)sp(4) we recover the famous integrable proton–neutron model of Richardson.

Related Topics
Physical Sciences and Engineering Mathematics Mathematical Physics
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