2,907 research outputs found
Evolution equation of entanglement for general bipartite systems
We explore how entanglement of a general bipartite system evolves when one
subsystem undergoes the action of an arbitrary noisy channel. It is found that
the dynamics of entanglement for general bipartite systems under the influence
of such channel is determined by the channel's action on the maximally
entangled state, which includes as a special case the results for two-qubit
systems [Nature Physics 4, 99 (2008)]. In particular, for multi-qubit or
qubit-qudit systems, we get a general factorization law for evolution equation
of entanglement with one qubit being subject to a noisy channel. Our results
can help the experimental characterization of entanglement dynamics.Comment: 4 pages, 1 figur
Phase Relations in the Li2O-V2O3-V2O5 System at 700 C: Correlations with Magnetic Defect Concentration in Heavy Fermion LiV2O4
The phase relations in the Li2O-V2O3-V2O5 ternary system at 700 C for
compositions in equilibrium with LiV2O4 are reported. This study clarified the
synthesis conditions under which low and high magnetic defect concentrations
can be obtained within the spinel structure of LiV2O4. We confirmed that the
LiV2O4 phase can be obtained containing low (0.006 mol%) to high (0.83 mol%)
magnetic defect concentrations n{defect} and with consistently high magnetic
defect spin S values between 3 and 6.5. The high n{defect} values were obtained
in the LiV2O4 phase in equilibrium with V2O3, Li3VO4, or LiVO2 and the low
values in the LiV2O4 phase in equilibrium with V3O5. A model is suggested to
explain this correlation.Comment: 6 pages, 7 figures; Phys. Rev. B (accepted
Identification, isolation and in vitro antimicrobial susceptibility testing of Aeromonas veronii associated with an acute death of Channel Catfish (Ictalurus lunetas) in China
Aeromonas veronii is a common pathogen in both humans and animals. It exists in the environment we live. Many reports showed it could lead to human infection but few demonstrated its effect on aquatic animals, especially Channel Catfish (Ictalurus lunetaus). Here, A. veronii was isolated from an acute death case of Channel Catfish in Southwestern China. This Gram-negative bacillus was identified by 16S rRNA sequencing. Antimicrobial susceptibility was also conducted to guide the treatment of the disease
Nutcrackers become choosy seed harvesters in a mast-crop year.
As an efficient seed-disperser, Eurasian nutcrackers (Nucifraga caryocatactes) generally consume and hoard mature, edible pine seeds for future use. In 2009, when the Arolla pine, Pinus. cembra, produced a mast-crop, we investigated cones discarded
by nutcrackers. Most cones were only partly eaten and some mature seeds remained in the distal part. This was in contrast to years of lower seed production when nearly all seeds were harvested from the majority of cones. To determine
whether nutcracker cone-discarding behaviour maximised intake rate, seed kernels and the aborted seeds rate were measured from the different cone parts. In 2009, seeds from cone-tops were on average 17% lighter than in the base and middle sections, and the proportion of aborted seeds in the top part was 81% higher than in the other sections. There was no difference in seed mass and proportion of aborted seeds in cone-tops of intact cones and cones handled by nutcrackers. Regarding each cone as a patch, cone discarding behaviour can be considered as an optimal cone-leaving rule, maximising rate of energy-intake, supporting the Marginal Value Theorem. Hence, we suggest that increased food abundance leads to more selective seed harvesting in nutcrackers
Neutrinos and Nucleosynthesis in Supernova
The type II supernova is considered as a candidate site for the production of
heavy elements. The nucleosynthesis occurs in an intense neutrino flux, we
calculate the electron fraction in this environment.Comment: RevTex4 style, 3 pages including 1 figure. Presented at Mexican
School of Astrophysics 2002, Guanajuato, Mexico, 31 Jul - 7 Aug 2002. Final
version to appear in the Proceedings of IX Mexican Workshop on Particles and
Fields Physics Beyond the Standard Model, Colima Col. Mexico, November 17-22,
200
Relaxation of Spin Polarized He in Mixtures of He and He Below the He Lambda Point
We report the first study of the depolarization behavior of spin polarized
3He in a mixture of 3He-4He at a temperature below the 4He Lambda point in a
deuterated TetraPhenyl Butadiene-doped deuterated PolyStyrene (dTPB-dPS) coated
acrylic cell. In our experiment the measured 3He relaxation time is due to the
convolution of the 3He longitudinal relaxation time, T1, and the diffusion time
constant of 3He in superfluid 4He since depolarization takes place on the
walls. We have obtained a 3He relaxation time ~3000 seconds at a temperature
around 1.9K. We have shown that it's possible to achieve values of wall
depolarization probability on the order of (1-2)x10^-7 for polarized 3He in the
superfluid 4He from a dTPB-dPS coated acrylic surface.Comment: The Model used to interpret the data has been change
A Unified Quantum NOT Gate
We study the feasibility of implementing a quantum NOT gate (approximate)
when the quantum state lies between two latitudes on the Bloch's sphere and
present an analytical formula for the optimized 1-to- quantum NOT gate. Our
result generalizes previous results concerning quantum NOT gate for a quantum
state distributed uniformly on the whole Bloch sphere as well as the phase
covariant quantum state. We have also shown that such 1-to- optimized NOT
gate can be implemented using a sequential generation scheme via matrix product
states (MPS)
Possible interpretation of the (10610) and (10650) in a chiral quark model
Motivated by the two charged bottomonium-like resonances (10610) and
(10650) newly observed by the Belle collaboration, the possible molecular
states composed of a pair of heavy mesons, , etc (in S-wave), are investigated in the framework of chiral quark
models by the Gaussian expansion method. The bound states and
with quantum numbers , which are good
candidates for the and respectively, are obtained.
Other three bound states with ,
with are predicted. These
states may be observed in open-bottom or hidden-bottom decay channel of highly
excited . When extending directly the quark model to the hidden color
channel of the multi-quark system, more deeply bound states are found. Future
experimental search of those states will cast doubt on the validity of applying
the chiral constituent quark model to the hidden color channel directly.Comment: 13 pages, 1 figure, title and some arguments in the abstract and
section 5 are revised, results unchange
SRSF1 modulates the organization of splicing factors in nuclear speckles and regulates transcription
The mammalian cell nucleus is compartmentalized into non-membranous subnuclear domains that regulate key nuclear functions. Nuclear speckles are subnuclear domains that contain pre-mRNA processing factors and non-coding RNAs. Many of the nuclear speckle constituents work in concert to coordinate multiple steps of gene expression, including transcription, pre-mRNA processing and mRNA transport. The mechanism that regulates the formation and maintenance of nuclear speckles in the interphase nucleus is poorly understood. In the present study, we provide evidence for the involvement of nuclear speckle resident proteins and RNA components in the organization of nuclear speckles. SR-family splicing factors and their binding partner, long non-coding MALAT1 RNA, can nucleate the assembly of nuclear speckles in the interphase nucleus. Depletion of SRSF1 in human cells compromises the association of splicing factors to nuclear speckles and influences the levels and activity of other SR proteins. Furthermore, on a stably integrated reporter gene locus, we demonstrate the role for SRSF1 in RNA polymerase II-mediated transcription. Our results suggest that SR proteins mediate the assembly of nuclear speckles and regulate gene expression by influencing both transcriptional and posttranscriptional activities within the cell nucleus
The Path Integral Monte Carlo Calculation of Electronic Forces
We describe a method to evaluate electronic forces by Path Integral Monte
Carlo (PIMC). Electronic correlations, as well as thermal effects, are included
naturally in this method. For fermions, a restricted approach is used to avoid
the ``sign'' problem. The PIMC force estimator is local and has a finite
variance. We applied this method to determine the bond length of H and the
chemical reaction barrier of H+HH+H. At low
temperature, good agreement is obtained with ground state calculations. We
studied the proton-proton interaction in an electron gas as a simple model for
hydrogen impurities in metals. We calculated the force between the two protons
at two electronic densities corresponding to Na () and Al
() using a supercell with 38 electrons. The result is compared to
previous calculations. We also studied the effect of temperature on the
proton-proton interaction. At very high temperature, our result agrees with the
Debye screening of electrons. As temperature decreases, the Debye theory fails
both because of the strong degeneracy of electrons and most importantly, the
formation of electronic bound states around the protons.Comment: 18 pages, 10 figure
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