30,183 research outputs found
A characterization of positive linear maps and criteria of entanglement for quantum states
Let and be (finite or infinite dimensional) complex Hilbert spaces. A
characterization of positive completely bounded normal linear maps from
into is given, which particularly gives a
characterization of positive elementary operators including all positive linear
maps between matrix algebras. This characterization is then applied give a
representation of quantum channels (operations) between infinite-dimensional
systems. A necessary and sufficient criterion of separability is give which
shows that a state on is separable if and only if
for all positive finite rank elementary operators
. Examples of NCP and indecomposable positive linear maps are given and
are used to recognize some entangled states that cannot be recognized by the
PPT criterion and the realignment criterion.Comment: 20 page
Necessary and sufficient conditions for local creation of quantum discord
We show that a local channel cannot create quantum discord (QD) for zero QD
states of size if and only if either it is a completely decohering
channel or it is a nontrivial isotropic channel. For the qubit case this
propertiy is additionally characteristic to the completely decohering channel
or the commutativity-preserving unital channel. In particular, the exact forms
of the completely decohering channel and the commutativity-preserving unital
qubit channel are proposed. Consequently, our results confirm and improve the
conjecture proposed by X. Hu et al. for the case of and improve the
result proposed by A. Streltsov et al. for the qubit case. Furthermore, it is
shown that a local channel nullifies QD in any state if and only if it is a
completely decohering channel. Based on our results, some protocols of quantum
information processing issues associated with QD, especially for the qubit
case, would be experimentally accessible.Comment: 8 page
On Singularity Formation of a Nonlinear Nonlocal System
We investigate the singularity formation of a nonlinear nonlocal system. This
nonlocal system is a simplified one-dimensional system of the 3D model that was
recently proposed by Hou and Lei in [13] for axisymmetric 3D incompressible
Navier-Stokes equations with swirl. The main difference between the 3D model of
Hou and Lei and the reformulated 3D Navier-Stokes equations is that the
convection term is neglected in the 3D model. In the nonlocal system we
consider in this paper, we replace the Riesz operator in the 3D model by the
Hilbert transform. One of the main results of this paper is that we prove
rigorously the finite time singularity formation of the nonlocal system for a
large class of smooth initial data with finite energy. We also prove the global
regularity for a class of smooth initial data. Numerical results will be
presented to demonstrate the asymptotically self-similar blow-up of the
solution. The blowup rate of the self-similar singularity of the nonlocal
system is similar to that of the 3D model.Comment: 28 pages, 9 figure
Is the Top Quark Really Heavier than the Boson?
Scalar induced top decays may drastically suppress
and still hide the top below . The collider experiments should
enlarge the scope and study the plane. Specific model
signatures such as (multiple high -jets) and
, (with $B(t\to b\tau\nu) \
\raisebox{-.5ex}{\rlap{}} \raisebox{.4ex}{}\ 1/3t^\primeb^\prime$ quark,
while top quark and toponium physics could still turn up at LEP-II.Comment: 11 pages (RevTex), 3 figures (not included), NTUTH-93-0
Antiviral treatment alters the frequency of activating and inhibitory receptor-expressing natural killer cells in chronic Hepatitis B virus infected patients
Natural killer (NK) cells play a critical role in innate antiviral immunity, but little is known about the impact of antiviral therapy on the frequency of NK cell subsets. To this aim, we performed this longitudinal study to examine the dynamic changes of the frequency of different subsets of NK cells in CHB patients after initiation of tenofovir or adefovir therapy. We found that NK cell numbers and subset distribution differ between CHB patients and normal subjects; furthermore, the association was found between ALT level and CD158b+ NK cell in HBV patients. In tenofovir group, the frequency of NK cells increased during the treatment accompanied by downregulated expression of NKG2A and KIR2DL3. In adefovir group, NK cell numbers did not differ during the treatment, but also accompanied by downregulated expression of NKG2A and KIR2DL3. Our results demonstrate that treatment with tenofovir leads to viral load reduction, and correlated with NK cell frequencies in peripheral blood of chronic hepatitis B virus infection. In addition, treatments with both tenofovir and adefovir in chronic HBV infected patients induce a decrease of the frequency of inhibitory receptor+ NK cells, which may account for the partial restoration of the function of NK cells in peripheral blood following treatment
Dynamical Mean-Field Theory within the Full-Potential Methods: Electronic structure of Ce-115 materials
We implemented the charge self-consistent combination of Density Functional
Theory and Dynamical Mean Field Theory (DMFT) in two full-potential methods,
the Augmented Plane Wave and the Linear Muffin-Tin Orbital methods. We
categorize the commonly used projection methods in terms of the causality of
the resulting DMFT equations and the amount of partial spectral weight
retained. The detailed flow of the Dynamical Mean Field algorithm is described,
including the computation of response functions such as transport coefficients.
We discuss the implementation of the impurity solvers based on hybridization
expansion and an analytic continuation method for self-energy. We also derive
the formalism for the bold continuous time quantum Monte Carlo method. We test
our method on a classic problem in strongly correlated physics, the
isostructural transition in Ce metal. We apply our method to the class of heavy
fermion materials CeIrIn_5, CeCoIn_5 and CeRhIn_5 and show that the Ce 4f
electrons are more localized in CeRhIn_5 than in the other two, a result
corroborated by experiment. We show that CeIrIn_5 is the most itinerant and has
a very anisotropic hybridization, pointing mostly towards the out-of-plane In
atoms. In CeRhIn_5 we stabilized the antiferromagnetic DMFT solution below 3K,
in close agreement with the experimental N\'eel temperature.Comment: The implementation of Bold-CTQMC added and some test of the method
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Thermonuclear Ti-42(p, gamma)V-43 rate in type-I x-ray bursts
The thermonuclear rate of the Ti-42(p, gamma)V-43 reaction has been reevaluated based on a recent precise proton separation energy measurement of S-p(V-43) = 83 +/- 43 keV. The astrophysical impact of our new rates has been investigated through one-zone postprocessing type-I x-ray burst calculations. It shows that the new experimental value of S-p significantly affects the yields of species for A approximate to 40-45. As well, the precision of the recent experimental S-p value constrains these yields to better than a factor of 3.Peer reviewedFinal Accepted Versio
New Physics Effects From B Meson Decays
In this talk, we point out some of the present and future possible signatures
of physics beyond the Standard Model from B-meson decays, taking R-parity
conserving and violating supersymmetry as illustrative examples.Comment: Talk given at the Sixth Workshop on High Energy Particle
Phenomenology (WHEPP-6), Chennai (Madras), India. Includes 2 epsf figure
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