6,885 research outputs found
Binomial Difference Ideal and Toric Difference Variety
In this paper, the concepts of binomial difference ideals and toric
difference varieties are defined and their properties are proved. Two canonical
representations for Laurent binomial difference ideals are given using the
reduced Groebner basis of Z[x]-lattices and regular and coherent difference
ascending chains, respectively. Criteria for a Laurent binomial difference
ideal to be reflexive, prime, well-mixed, perfect, and toric are given in terms
of their support lattices which are Z[x]-lattices. The reflexive, well-mixed,
and perfect closures of a Laurent binomial difference ideal are shown to be
binomial. Four equivalent definitions for toric difference varieties are
presented. Finally, algorithms are given to check whether a given Laurent
binomial difference ideal I is reflexive, prime, well-mixed, perfect, or toric,
and in the negative case, to compute the reflexive, well-mixed, and perfect
closures of I. An algorithm is given to decompose a finitely generated perfect
binomial difference ideal as the intersection of reflexive prime binomial
difference ideals.Comment: 72 page
Kondo Spin Screening Cloud in Two-dimensional Electron Gas with Spin-orbit Couplings
A spin-1/2 Anderson impurity in a semiconductor quantum well with Rashba and
Dresselhaus spin-orbit couplings is studied by using a variational wave
function method. The local magnetic moment is found to be quenched at low
temperatures. The spin-spin correlations of the impurity and the conduction
electron density show anisotropy in both spatial and spin spaces, which
interpolates the Kondo spin screenings of a conventional metal and of a surface
of three-dimensional topological insulators.Comment: accepted by the Journal of Physics: Condensed Matte
Bose-Einstein condensation in strong-coupling quark color superconductor near flavor SU(3) limit
Near the flavor SU(3) limit, we propose an analytical description for
color-flavor-locked-type Bardeen-Cooper-Schrieffer (BCS) phase in the Nambu
Jona-Lasinio (NJL) model. The diquark behaviors in light-flavor and
strange-flavor-involved channels and Bose-Einstein condensation (BEC) of bound
diquark states are studied. When the attractive interaction between quarks is
strong enough, a BCS-BEC crossover is predicted in the environment with
color-flavor-locked pairing pattern. The resulting Bose-Einstein condensed
phase is found to be an intergrade phase before the emergence of the
previous-predicted BEC phase in two-flavor quark superconductor.Comment: 15 pages, 5 figures; 2nd versio
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