10,843 research outputs found
Chiral Perturbation Theory and U(3)_L\times U(3)_R Chiral Theory of Mesons
We examine low energy limit of chiral theory of mesons
through integrating out fields of vector and axial-vector mesons. The effective
lagrangian for pseudoscalar mesons at has been obtained, and five low
energy coupling constants have been revealed. They are in
good agreement with the results of CHPT's at .Comment: 20 pages, Standard LaTex file, no finger
Experimental Realization of Br\"{u}schweiler's exponentially fast search algorithm in a homo-nuclear system
Compared with classical search algorithms, Grover quantum algorithm [ Phys.
Rev. Lett., 79, 325(1997)] achieves quadratic speedup and Bruschweiler hybrid
quantum algorithm [Phys. Rev. Lett., 85, 4815(2000)] achieves an exponential
speedup. In this paper, we report the experimental realization of the
Bruschweiler$ algorithm in a 3-qubit NMR ensemble system. The pulse sequences
are used for the algorithms and the measurement method used here is improved on
that used by Bruschweiler, namely, instead of quantitatively measuring the spin
projection of the ancilla bit, we utilize the shape of the ancilla bit
spectrum. By simply judging the downwardness or upwardness of the corresponding
peaks in an ancilla bit spectrum, the bit value of the marked state can be read
out, especially, the geometric nature of this read-out can make the results
more robust against errors.Comment: 10 pages and 3 figure
Nanoplasmonics beyond Ohm's law
In tiny metallic nanostructures, quantum confinement and nonlocal response
change the collective plasmonic behavior with important consequences for e.g.
field-enhancement and extinction cross sections. We report on our most recent
developments of a real-space formulation of an equation-of-motion that goes
beyond the common local-response approximation and use of Ohm's law as the
central constitutive equation. The electron gas is treated within a
semi-classical hydrodynamic model with the emergence of a new intrinsic length
scale. We briefly review the new governing wave equations and give examples of
applying the nonlocal framework to calculation of extinction cross sections and
field enhancement in isolated particles, dimers, and corrugated surfaces.Comment: Invited paper for TaCoNa-Photonics 2012 (www.tacona-photonics.org),
to appear in AIP Conf. Pro
New spectrum of negative-parity doubly charmed baryons: Possibility of two quasistable states
The discovery of by the LHCb Collaboration triggers
predictions of more doubly charmed baryons. By taking into account both the
-wave excitations between the two charm quarks and the scattering of light
pseudoscalar mesons off the ground state doubly charmed baryons, a set of
negative-parity spin-1/2 doubly charmed baryons are predicted already from a
unitarized version of leading order chiral perturbation theory. Moreover,
employing heavy antiquark-diquark symmetry the relevant low-energy constants in
the next-to-leading order are connected with those describing light
pseudoscalar mesons scattering off charmed mesons, which have been well
determined from lattice calculations and experimental data. Our calculations
result in a spectrum richer than that of heavy mesons. We find two very narrow
, which very likely decay into
breaking isospin symmetry. In the isospin-1/2 sector, three states
are predicted to exist below 4.2~GeV with the lowest one being narrow and the
other two rather broad. We suggest to search for the states in
the mode. Searching for them and their analogues are
helpful to establish the hadron spectrum.Comment: 6 pages, 3 figures; accepted for publication as a Rapid Communication
in Physical Review
Variation of the Fine-Structure Constant from the de Sitter Invariant Special Relativity
There are obvious discrepancies among various experimental constraints on the
variation of the fine-structure constant, . We attempt to discuss the
issue in the framework of de Sitter invariant Special Relativity () and to present a possible solution to the disagreement. In
addition, on the basis of the observational data and the discussions presented
in this Letter, we derive a rough theoretical estimate of the radius of the
Universe.Comment: 8 pages, no figure
Depleted Energy Charge and Increased Pulmonary Endothelial Permeability Induced by Mitochondrial Complex I inhibition are Mitigated by Coenzyme Q\u3csub\u3e1\u3c/sub\u3e in the Isolated Perfused Rat Lung
Mitochondrial dysfunction is associated with various forms of lung injury and disease that also involve alterations in pulmonary endothelial permeability, but the relationship, if any, between the two is not well understood. This question was addressed by perfusing isolated intact rat lung with a buffered physiological saline solution in the absence or presence of the mitochondrial complex I inhibitor rotenone (20 ÎŒM). Compared to control, rotenone depressed whole lung tissue ATP from 5.66±0.46 (SEM) to 2.34±0.15 ”mol·gâ1 dry lung, with concomitant increases in the ADP:ATP and AMP:ATP ratios. Rotenone also increased lung perfusate lactate (from 12.36±1.64 to 38.62±3.14 ”mol·15 minâ1 perfusion·gâ1 dry lung) and the lactate:pyruvate ratio, but had no detectable impact on lung tissue GSH:GSSG redox status. The amphipathic quinone coenzyme Q1 (CoQ1; 50 ÎŒM) mitigated the impact of rotenone on the adenine nucleotide balance, wherein mitigation was blocked by NAD(P)H-quinone oxidoreductase 1 or mitochondrial complex III inhibitors. In separate studies, rotenone increased the pulmonary vascular endothelial filtration coefficient (Kf) from 0.043±0.010 to 0.156±0.037 ml·minâ1·cm H2Oâ1·gâ1 dry lung, and CoQ1 protected against the effect of rotenone on Kf. A second complex I inhibitor, piericidin A, qualitatively reproduced the impact of rotenone on Kf and the lactate:pyruvate ratio. Taken together, the observations imply that pulmonary endothelial barrier integrity depends on mitochondrial bioenergetics as reflected in lung tissue ATP levels and that compensatory activation of whole lung glycolysis cannot protect against pulmonary endothelial hyperpermeability in response to mitochondrial blockade. The study further suggests that low-molecular-weight amphipathic quinones may have therapeutic utility in protecting lung barrier function in mitochondrial insufficiency
Influence of charge status on the stress safety properties of Li(NiâââCoâââMnâââ)Oâ cells
In order to improve safety management, the stress changes of Li(Ni1/3Co1/3Mn1/3)O2 (NMC) cells are real-time monitored using non-destructive strain gauges, and the effects of gauge substrate, temperature and state-of-charge (SOC) have been investigated. The shell exhibits elastic deformation behaviour, and the strain-stress relationship is established. As the temperature increases from 25 to 80 °C, the stress of the NMC cells increases from 0 to 275 MPa, especially greatly at 70 °C and sharply at 80 °C after 18 h. The stress increases from 0 to 9.2 MPa when the potential increases from 2.8 to 4.3 V. However, the value rises from 10 to 55 MPa when the voltage increases from 4.6 to 5.0 V during the over-charge process. An obvious increase of stress appears when the cut-off voltage is below 0.6 V during over-discharge tests. The facile method is significant for non-destructive inspection and emergency management of batteries
Electrical Control of Two-Dimensional Neutral and Charged Excitons in a Monolayer Semiconductor
Monolayer group VI transition metal dichalcogenides have recently emerged as
semiconducting alternatives to graphene in which the true two-dimensionality
(2D) is expected to illuminate new semiconducting physics. Here we investigate
excitons and trions (their singly charged counterparts) which have thus far
been challenging to generate and control in the ultimate 2D limit. Utilizing
high quality monolayer molybdenum diselenide (MoSe2), we report the unambiguous
observation and electrostatic tunability of charging effects in positively
charged (X+), neutral (Xo), and negatively charged (X-) excitons in field
effect transistors via photoluminescence. The trion charging energy is large
(30 meV), enhanced by strong confinement and heavy effective masses, while the
linewidth is narrow (5 meV) at temperatures below 55 K. This is greater
spectral contrast than in any known quasi-2D system. We also find the charging
energies for X+ and X- to be nearly identical implying the same effective mass
for electrons and holes.Comment: 11 pages main text with 4 figures + 7 pages supplemental material
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