arXiv subjects
Publications and source records attributed to Chi Au.
Making use of symmetry properties and known exact results for the Hubbard Model on bipartite lattice, we show that (1) there is no phase separation for repulsive coupling at low dopings, (2) phase separation and superconductivity co-exist in the ground states for attractive coupling in a range of filling fractions.
It has been shown that the electron system with ODLRO in the reduced density matrix $ρ_2$ can not support a uniform magnetic field, i.e., ODLRO\ in $% ρ_2$ implies the Meissner effect \cite{2}\cite{3}, furthermore, the magnetic field trapped in the system is quantized\cite{3}. This note extends above results in two cases. We show that (1) the system with ODLRO in $ρ_2$ can not support a non uniform, cylindrically symmetric magnetic field; (2) the system with ODLRO in $ρ_2$ can not support a magnetic field slowly varying in space, and the magnetic flux trapped in it is quantized.