60,133 research outputs found
Entanglement Polygon Inequality in Qubit Systems
We prove a set of tight entanglement inequalities for arbitrary -qubit
pure states. By focusing on all bi-partite marginal entanglements between each
single qubit and its remaining partners, we show that the inequalities provide
an upper bound for each marginal entanglement, while the known monogamy
relation establishes the lower bound. The restrictions and sharing properties
associated with the inequalities are further analyzed with a geometric polytope
approach, and examples of three-qubit GHZ-class and W-class entangled states
are presented to illustrate the results.Comment: 8 pages, 4 figure
The effects of Zn Impurity on the Properties of Doped Cuprates in the Normal State
We study the interplay of quantum impurity, and collective spinon and holon
dynamics in Zn doped high-T cuprates in the normal state. The
two-dimensional t-t-J models with one and a small amount of Zn
impurity are investigated within a numerical method based on the double-time
Green function theory. We study the inhomogeneities of holon density and
antiferromagnetic correlation background in cases with different Zn
concentrations, and obtain that doped holes tend to assemble around the Zn
impurity with their mobility being reduced. Therefore a bound state of holon is
formed around the nonmagnetic Zn impurity with the effect helping Zn to
introduce local antiferromagnetism around itself. The incommensurate peaks we
obtained in the spin structure factor indicate that Zn impurities have effects
on mixing the q=(, ) and q=0 components in spin excitations.Comment: 5 pages, 3 figure
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