arXiv subjects

Jonathan P. Wallington

Publications and source records attributed to Jonathan P. Wallington.

2 recordsLinked to original sources

arXiv1998

S- and D-Wave Pairing in Short Coherence Length Superconductors

We derive an appropriate Landau-Ginzburg-Wilson effective action to describe the nearest neighbour attractive Hubbard model. This allows us to discuss both the small V (BCS) limit and the large V (Bose-Einstein) limit within the same framework. The model is particularly interesting as it exhibits both extended s-wave and d-wave solutions as well as an intermediate s+id phase and an unstable p-wave phase. We note that in the large V limit, as pairs become localised on bonds, the s- and d-wave solutions become degenerate.

cond-mat.supr-con↗

arXiv1997

Discrete Symmetries and Transformations of the Hubbard Model

We show that, in addition to SO(4), the Hubbard model at half filling on a bipartite lattice has a group of discrete symmetries and transformations. A unique Hubbard-Stratonovich decomposition of the interaction term, incorporating both spin and pseudospin variables on an equal footing, is found in which these symmetries are manifestly present. The consequences of this at the mean field and one loop renormalisation group levels are discussed.

cond-mat.str-el↗