8,150 research outputs found
The Complexity of Vector Spin Glasses
We study the annealed complexity of the m-vector spin glasses in the
Sherrington-Kirkpatrick limit. The eigenvalue spectrum of the Hessian matrix of
the Thouless-Anderson-Palmer (TAP) free energy is found to consist of a
continuous band of positive eigenvalues in addition to an isolated eigenvalue
and (m-1) null eigenvalues due to rotational invariance. Rather surprisingly,
the band does not extend to zero at any finite temperature. The isolated
eigenvalue becomes zero in the thermodynamic limit, as in the Ising case (m=1),
indicating that the same supersymmetry breaking recently found in Ising spin
glasses occurs in vector spin glasses.Comment: 4 pages, 2 figure
Teleportation with a Mixed State of Four Qubits and the Generalized Singlet Fraction
Recently, an explicit protocol for faithfully teleporting
arbitrary two-qubit states using genuine four-qubit entangled states was
presented by us [Phys. Rev. Lett. {\bf 96}, 060502 (2006)]. Here, we show that
with an arbitrary four-qubit mixed state resource is
equivalent to a generalized depolarizing bichannel with probabilities given by
the maximally entangled components of the resource. These are defined in terms
of our four-qubit entangled states. We define the generalized singlet fraction
, and illustrate its physical significance with several
examples. We argue that in order to teleport arbitrary two-qubit states with
average fidelity better than is classically possible, we have to demand that
. In addition, we conjecture that when then no entanglement can be teleported. It is shown that to determine the
usefulness of for , it is necessary to analyze .Comment: 11 page
Torque magnetometry studies of new low temperature metamagnetic states in ErNi_{2}B_{2}C
The metamagnetic transitions in single-crystal ErNiBC have been
studied at 1.9 K with a Quantum Design torque magnetometer. The critical fields
of the transitions depend crucially on the angle between applied field and the
easy axis [100]. Torque measurements have been made while changing angular
direction of the magnetic field (parallel to basal tetragonal -planes) in a
wide angular range (more than two quadrants). Sequences of metamagnetic
transitions with increasing field are found to be different for the magnetic
field along (or close enough to) the easy [100] axis from that near the hard
[110] axis. The study have revealed new metamagnetic states in ErNiBC
which were not apparent in previous longitudinal-magnetization and neutron
studies.Comment: 3 pages (4 figs. incl.) reported at 52th Magnetism and Magnetic
Materials Conference, Tampa, Florida, USA, November 200
Teleportation and Dense Coding with Genuine Multipartite Entanglement
We present an explicit protocol for faithfully teleporting an
arbitrary two-qubit state via a genunie four-qubit entangled state. By
construction, our four-partite state is not reducible to a pair of Bell states.
Its properties are compared and contrasted with those of the four-party GHZ and
W states. We also give a dense coding scheme involving our state
as a shared resource of entanglement. Both and
indicate that our four-qubit state is a likely candidate for the genunine
four-partite analogue to a Bell state.Comment: 9 pages, 0 figur
Inhibition of oncogenic transcription factor REL by the natural product derivative calafianin monomer 101 induces proliferation arrest and apoptosis in human B-lymphoma cell lines
Increased activity of transcription factor NF-κB has been implicated in many B-cell lymphomas. We investigated effects of synthetic compound calafianin monomer (CM101) on biochemical and biological properties of NF-κB. In human 293 cells, CM101 selectively inhibited DNA binding by overexpressed NF-κB subunits REL (human c-Rel) and p65 as compared to NF-κB p50, and inhibition of REL and p65 DNA binding by CM101 required a conserved cysteine residue. CM101 also inhibited DNA binding by REL in human B-lymphoma cell lines, and the sensitivity of several B-lymphoma cell lines to CM101-induced proliferation arrest and apoptosis correlated with levels of cellular and nuclear REL. CM101 treatment induced both phosphorylation and decreased expression of anti-apoptotic protein Bcl-XL, a REL target gene product, in sensitive B-lymphoma cell lines. Ectopic expression of Bcl-XL protected SUDHL-2 B-lymphoma cells against CM101-induced apoptosis, and overexpression of a transforming mutant of REL decreased the sensitivity of BJAB B-lymphoma cells to CM101-induced apoptosis. Lipopolysaccharide-induced activation of NF-κB signaling upstream components occurred in RAW264.7 macrophages at CM101 concentrations that blocked NF-κB DNA binding. Direct inhibitors of REL may be useful for treating B-cell lymphomas in which REL is active, and may inhibit B-lymphoma cell growth at doses that do not affect some immune-related responses in normal cells.R01 GM094551 - NIGMS NIH HHS; P50 GM067041 - NIGMS NIH HHS; GM094551 - NIGMS NIH HHS; R24 GM111625 - NIGMS NIH HHS; GM067041 - NIGMS NIH HH
Time correlated quantum amplitude damping channel
We analyze the problem of sending classical information through qubit
channels where successive uses of the channel are correlated. This work extends
the analysis of C. Macchiavello and G. M. Palma to the case of a non-Pauli
channel - the amplitude damping channel. Using the channel description outlined
in S. Daffer, et al, we derive the correlated amplitude damping channel. We
obtain a similar result to C. Macchiavello and G. M. Palma, that is, that under
certain conditions on the degree of channel memory, the use of entangled input
signals may enhance the information transmission compared to the use of product
input signals.Comment: 9 pages, REVTex
Affleck-Dine Baryogenesis, Split Supersymmetry, and Inflation
It is shown that, in the context of split supersymmetry, a simple model with
a single complex scalar field can produce chaotic inflation and generate the
observed amount of baryon asymmetry via the Affleck-Dine mechanism. While the
inflaton quantum fluctuations give rise to curvature perturbation, we show that
quantum fluctuations of the phase of the scalar field can produce baryonic
isocurvature perturbation. Combining with constraints from WMAP data, all
parameters in the model can be determined to within a narrow range.Comment: version accepted for publication in PR
Effects of Collisional Decoherence on Multipartite Entanglement - How would entanglement not be relatively common?
We consider the collision model of Ziman {\em et al.} and study the
robustness of -qubit Greenberger-Horne-Zeilinger (GHZ), W, and linear
cluster states. Our results show that -qubit entanglement of GHZ states
would be extremely fragile under collisional decoherence, and that of W states
could be more robust than of linear cluster states. We indicate that the
collision model of Ziman {\em et al.} could provide a physical mechanism to
some known results in this area of investigations. More importantly, we show
that it could give a clue as to how -partite distillable entanglement would
be relatively rare in our macroscopic classical world.Comment: 10 page
Electric tempest in a teacup: the tea leaf analogy to microfluidic blood plasma separation
In a similar fashion to Einstein's tea leaf paradox, the rotational liquid flow induced by ionic wind above a liquid surface can trap suspended microparticles by a helical motion, spinning them down towards a bottom stagnation point. The motion is similar to Batchelor [Q. J. Mech. Appl. Math. 4, 29 (1951)] flows occurring between stationary and rotating disks and arises due to a combination of the primary azimuthal and secondary bulk meridional recirculation that produces a centrifugal and enhanced inward radial force near the chamber bottom. The technology is thus useful for microfluidic particle trapping/concentration; the authors demonstrate its potential for rapid erythrocyte/blood plasma separation for miniaturized medical diagnostic kits
Chevalier Jackson, M.D. (1865-1958): Il ne se repose jamais.
In the final year of the American Civil War, 1865, Chevalier Jackson was born on the 4th of November just outside Pittsburgh, Pennsylvania. The eldest of three sons of a poor, livestock-raising family, Jackson was raised in a period of social and political unrest. He was perhaps an even more unrestful boy. The description of his childhood days from his father’s father—Il ne se repose jamais, ‘‘He never rests’’—would ultimately reflect the man, doctor, and evangelist Jackson would later become.1 Indeed, he never did rest, Jackson would tirelessly pave the way for modern bronchoscopy and endoscopy as a whole; bringing international renown not only to himself, but also to his specialty
- …