26,527 research outputs found
Conditions for entanglement transformation between a class of multipartite pure states with generalized Schmidt decompositions
In this note we generalize Nielsen's marjoization criterion for the
convertibility of bipartite pure states [Phys. Rev. Lett \textbf{83},
436(1999)] to a special class of multipartite pure states which have
generalized Schmidt decompositions.Comment: 3 pages (Revetex 4), no figures. A brief note on entanglement
transformation. Comments are welcom
Topological current of point defects and its bifurcation
From the topological properties of a three dimensional vector order
parameter, the topological current of point defects is obtained. One shows that
the charge of point defects is determined by Hopf indices and Brouwer degrees.
The evolution of point defects is also studied. One concludes that there exist
crucial cases of branch processes in the evolution of point defects when the
Jacobian .Comment: revtex,14 pages,no figur
Topology of Knotted Optical Vortices
Optical vortices as topological objects exist ubiquitously in nature. In this
paper, by making use of the -mapping topological current theory, we
investigate the topology in the closed and knotted optical vortices. The
topological inner structure of the optical vortices are obtained, and the
linking of the knotted optical vortices is also given.Comment: 11 pages, no figures, accepted by Commun. Theor. Phys. (Beijing, P.
R. China
Comment on "Quantum Phase Slips and Transport in Ultrathin Superconducting Wires"
In a recent Letter (Phys. Rev. Lett.78, 1552 (1997) ), Zaikin, Golubev, van
Otterlo, and Zimanyi criticized the phenomenological time-dependent
Ginzburg-Laudau model which I used to study the quantum phase-slippage rate for
superconducting wires. They claimed that they developed a "microscopic" model,
made qualitative improvement on my overestimate of the tunnelling barrier due
to electromagnetic field. In this comment, I want to point out that, i), ZGVZ's
result on EM barrier is expected in my paper; ii), their work is also
phenomenological; iii), their renormalization scheme is fundamentally flawed;
iv), they underestimated the barrier for ultrathin wires; v), their comparison
with experiments is incorrect.Comment: Substantial changes made. Zaikin et al's main result was expected
from my work. They underestimated tunneling barrier for ultrathin wires by
one order of magnitude in the exponen
Evolution of the Chern-Simons Vortices
Based on the gauge potential decomposition theory and the -mapping
theory, the topological inner structure of the Chern-Simons-Higgs vortex has
been showed in detail. The evolution of CSH vortices is studied from the
topological properties of the Higgs scalar field. The vortices are found
generating or annihilating at the limit points and encountering, splitting or
merging at the bifurcation points of the scalar field Comment: 10 pages, 10 figure
Three-dimensional theory for interaction between atomic ensembles and free-space light
Atomic ensembles have shown to be a promising candidate for implementations
of quantum information processing by many recently-discovered schemes. All
these schemes are based on the interaction between optical beams and atomic
ensembles. For description of these interactions, one assumed either a
cavity-QED model or a one-dimensional light propagation model, which is still
inadequate for a full prediction and understanding of most of the current
experimental efforts which are actually taken in the three-dimensional free
space. Here, we propose a perturbative theory to describe the three-dimensional
effects in interaction between atomic ensembles and free-space light with a
level configuration important for several applications. The calculations reveal
some significant effects which are not known before from the other approaches,
such as the inherent mode-mismatching noise and the optimal mode-matching
conditions. The three-dimensional theory confirms the collective enhancement of
the signal-to-noise ratio which is believed to be one of the main advantage of
the ensemble-based quantum information processing schemes, however, it also
shows that this enhancement need to be understood in a more subtle way with an
appropriate mode matching method.Comment: 16 pages, 9 figure
Angular Momentum Conservation Law for Randall-Sundrum Models
In Randall-Sundrum models, by the use of general Noether theorem, the
covariant angular momentum conservation law is obtained with the respect to the
local Lorentz transformations. The angular momentum current has also
superpotential and is therefore identically conserved. The space-like
components of the angular momentum for Randall-Sundrum models are
zero. But the component is infinite.Comment: 10 pages, no figures, accepted by Mod. Phys. Lett.
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