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Bao-Heng Zhao

Publications and source records attributed to Bao-Heng Zhao.

7 recordsLinked to original sources
arXiv2004

Magnetoresistance in the s-d Model with Arbitrary Impurity Spin

The magnetoresistance, the number of the localized electrons, and the s-wave scattering phase shift at the Fermi level for the s-d model with arbitrary impurity spin are obtained in the ground state. To obtain above results some known exact results of the Bethe ansatz method are used. As the impurity spin S = 1/2, our results coincide with those obtained by Ishii \textit{et al%}. The compairsion between the theoretical and experimental magneticresistence for impurity S = 1/2 is re-examined.

cond-mat.str-el↗
arXiv2002

Quantum Integrable System with Multi-components in Two-Dimension

A quantum N-body problem with 2-component in (2+1)-dimension deduced from integrable model in (2+1) dimension is investigated. The Davey-Stewartson 1(DS1) system[Proc. R. Soc. London, Ser. A {\bf 338}, 101 (1974)] is an integrable model in two dimensions. A quantum DS1 system with 2 colour-components in two dimensions has been formulated. This two-dimensional problem has been reduced to two one-dimensional many-body problems with 2 colour-components. The solutions of the two-dimensional problem under consideration has been constructed from the resulting problems in one dimensions. For latters with the $δ$-function interactions and being solved by the Bethe-Yang ansatz, we introduce symmetrical and antisymmetrical Young operators of the permutation group and obtain the exact solutions for the quantum DS1 system. The application of the solusions is discussed.

cond-mat.stat-mech↗
arXiv1996

Phase separation in the Hubbard Model

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.

cond-mat↗
arXiv1995

From ODLRO to the Meissner Effect and Flux Quantization

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.

cond-mat↗
arXiv1994

Long-Range Correlation of Electron Pairs in the Hubbard Model at Finite Temperatures in Three Dimensions

We show that in the translation invariant case and in the antiferromagnetic phase, the reduced density matrix $ρ_2$ has no off-diagonal long-range order of on-site electron pairs for the single-band Hubbard model on a cubic lattice away from half filling at finite temperatures both for the positive coupling and for the negative coupling. In these cases the model can not give a mechanism for the superconductivity caused by the condensation of on-site electron pairs and the nearest-neighbor electron pairs.

cond-mat↗
arXiv1994

Off-Diagonal Long-Range Order: Meissner Effect and Flux Quantization

There has been a proof by Sewell that the hypothesis of off-diagonal long-range order in the reduced density matrix $ρ_2$ implies the Meissner effect. We present in this note an elementary and straightforward proof that not only the Meissner effect but also the property of magnetic flux quantization follows from the hypothesis. It is explicitly shown that the two phenomena are closely related, and phase coherence is the origin for both.

cond-mat↗