744 research outputs found
Microscopic reversibility of quantum open systems
The transition probability for time-dependent unitary evolution is invariant
under the reversal of protocols just as in the classical Liouvillian dynamics.
In this article, we generalize the expression of microscopic reversibility to
externally perturbed large quantum open systems. The time-dependent external
perturbation acts on the subsystem during a transient duration, and
subsequently the perturbation is switched off so that the total system would
thermalize. We concern with the transition probability for the subsystem
between the initial and final eigenstates of the subsystem. In the course of
time evolution, the energy is irreversibly exchanged between the subsystem and
reservoir. The time reversed probability is given by the reversal of the
protocol and the initial ensemble. Microscopic reversibility equates the time
forward and reversed probabilities, and therefore appears as a thermodynamic
symmetry for open quantum systems.Comment: numerical demonstration is correcte
Search for doubly charged Higgs bosons using the same-sign diboson mode at the LHC
Doubly charged Higgs bosons are predicted in many new physics models with an
extended Higgs sector that contains a Higgs triplet field. Current experimental
searches have been focusing mainly on the scenario in which the same-sign
dilepton decay modes are the dominant ones. We study the scenario where the
vacuum expectation value of the triplet field is sufficiently large so that the
associated charged Higgs bosons decay dominantly to a pair of weak gauge bosons
instead. A detailed simulation of the signal and the backgrounds is performed
for the CERN Large Hadron Collider at the collision energy of 8 TeV and 14 TeV.
We find that different cuts should be imposed for the events, depending on
whether the doubly charged Higgs boson mass is greater than about 200 GeV. In
the higher mass region, the forward jet tagging proves to be useful in
enhancing the signal significance. We show the discovery reach of the LHC
running at 8 and 14 TeV, with two benchmark triplet vacuum expectation values.
With an integrated luminosity of 10 fb at 8 TeV, the doubly charged
Higgs boson with a mass of GeV can be tested at level in
such a scenario.Comment: 18 pages, 10 figures; published in Physical Review
Effect of an InP/InGaAs Interface on Spin-orbit Interaction in InAlAs/InGaAs Heterostructures
We report the effect of the insertion of an InP/InGaAs
Interface on Rashba spin-orbit interaction in
InAlAs/InGaAs quantum wells. A small spin
split-off energy in InP produces a very intriguing band lineup in the valence
bands in this system. With or without this InP layer above the
InGaAs well, the overall values of the spin-orbit coupling
constant turned out to be enhanced or diminished for samples with the
front- or back-doping position, respectively. These experimental results, using
weak antilocalization analysis, are compared with the results of the
theory. The actual conditions of the interfaces and
materials should account for the quantitative difference in magnitude between
the measurements and calculations.Comment: Submitted for publication; v2 to adjust Eq.6; v3 to correct the
figure file name; v4, a revised version accepted for publication in Phys.
Rev.
Disability Prevention Programs for Older People: Factors Associated with Medical and Nursing Care Costs
This study aimed to clarify factors associated with medical and nursing care costs for older people living in community and to suggest an effective disability prevention programs. Total of participants in this study was 83 individuals (29 men and 54 women; mean age 81.2 ± 6.3 years old) on November 1st – December 28th, 2014. This study compared the average medical and nursing care costs per month with national average for those aged ≥ 65 years old. Logistic regression test was conducted to examine its association with medical and nursing care costs. Those who had outing activities ≥ 3 times a week were approximately three times less likely to reduce medical and nursing care costs than those who had outing activities < 3 times a week despite three controlled covariates (OR = 3.23 and 95% CI = 1.03 – 10.42). Disability prevention programs that improve frequency of outing at least three times in a week may become a valid economic approach to older people who do not live in nursing home
Anomalous pinning behavior in an incommensurate two-chain model of friction
Pinning phenomena in an incommensurate two-chain model of friction are
studied numerically. The pinning effect due to the breaking of analyticity
exists in the present model. The pinning behavior is, however, quite different
from that for the breaking of analyticity state of the Frenkel-Kontorova model.
When the elasticity of chains or the strength of interchain interaction is
changed, pinning force and maximum static frictional force show anomalously
complicated behavior accompanied by a successive phase transition and they
vanish completely under certain conditions.Comment: RevTex, 9 pages, 19 figures, to appear in Phys. Rev. B58 No.23(1998
Friction, order, and transverse pinning of a two-dimensional elastic lattice under periodic and impurity potentials
Frictional phenomena of two-dimensional elastic lattices are studied
numerically based on a two-dimensional Frenkel-Kontorova model with impurities.
It is shown that impurities can assist the depinning. We also investigate
anisotropic ordering and transverse pinning effects of sliding lattices, which
are characteristic of the moving Bragg glass state and/or transverse glass
state. Peculiar velocity dependence of the transverse pinning is observed in
the presence of both periodic and random potentials and discussed in the
relation with growing order and discommensurate structures.Comment: RevTeX, 4 pages, 5 figures. to appear in Phys. Rev. B Rapid Commu
TC83 Sequelae
Long-term neurological complications, termed sequelae, can result from viral encephalitis, which are not well understood. In human survivors, alphavirus encephalitis can cause severe neurobehavioral changes, in the most extreme cases, a schizophrenic-like syndrome. In the present study, we aimed to adapt an animal model of alphavirus infection survival to study the development of these long-term neurological complications. Upon low-dose infection of wild-type C57B/6 mice, asymptomatic and symptomatic groups were established and compared to mock-infected mice to measure general health and baseline neurological function, including the acoustic startle response and prepulse inhibition paradigm. Prepulse inhibition is a robust operational measure of sensorimotor gating, a fundamental form of information processing. Deficits in prepulse inhibition manifest as the inability to filter out extraneous sensory stimuli. Sensory gating is disrupted in schizophrenia and other mental disorders, as well as neurodegenerative diseases. Symptomatic mice developed deficits in prepulse inhibition that lasted through 6 months post infection; these deficits were absent in asymptomatic or mock-infected groups. Accompanying prepulse inhibition deficits, symptomatic animals exhibited thalamus damage as visualized with H&E staining, as well as increased GFAP expression in the posterior complex of the thalamus and dentate gyrus of the hippocampus. These histological changes and increased GFAP expression were absent in the asymptomatic and mock-infected animals, indicating that glial scarring could have contributed to the prepulse inhibition phenotype observed in the symptomatic animals. This model provides a tool to test mechanisms of and treatments for the neurological sequelae of viral encephalitis and begins to delineate potential explanations for the development of such sequelae post infection
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