6,413 research outputs found
A test of "fluctuation theorem" in non-Markovian open quantum systems
We study fluctuation theorems for open quantum systems with a non-Markovian
heat bath using the approach of quantum master equations and examine the
physical quantities that appear in those fluctuation theorems. The approach of
Markovian quantum master equations to the fluctuation theorems was developed by
Esposito and Mukamel [Phys. Rev. E {\bf73}, 046129 (2006)]. We show that their
discussion can be formally generalized to the case of a non-Markovian heat bath
when the local system is linearly connected to a Gaussian heat bath with the
spectrum distribution of the Drude form. We found by numerically simulating the
spin-boson model in non-Markovian regime that the "detailed balance" condition
is well satisfied except in a strongly non-equilibrium transient situation, and
hence our generalization of the definition of the "entropy production" is
almost always legitimate. Therefore, our generalization of the fluctuation
theorem seems meaningful in wide regions.Comment: 21 pages, 5 figure
Generalized Gauge Theories and Weinberg-Salam Model with Dirac-K\"ahler Fermions
We extend previously proposed generalized gauge theory formulation of
Chern-Simons type and topological Yang-Mills type actions into Yang-Mills type
actions. We formulate gauge fields and Dirac-K\"ahler matter fermions by all
degrees of differential forms. The simplest version of the model which includes
only zero and one form gauge fields accommodated with the graded Lie algebra of
supergroup leads Weinberg-Salam model. Thus the Weinberg-Salam model
formulated by noncommutative geometry is a particular example of the present
formulation.Comment: 33 pages, LaTe
Search for Scaling Dimensions for Random Surfaces with c=1
We study numerically the fractal structure of the intrinsic geometry of
random surfaces coupled to matter fields with . Using baby universe
surgery it was possible to simulate randomly triangulated surfaces made of
260.000 triangles. Our results are consistent with the theoretical prediction
for the intrinsic Hausdorff dimension.Comment: 10 pages, (csh will uudecode and uncompress ps-file), NBI-HE-94-3
N=2 Supersymmetric Model with Dirac-Kahler Fermions from Generalized Gauge Theory in Two Dimensions
We investigate the generalized gauge theory which has been proposed
previously and show that in two dimensions the instanton gauge fixing of the
generalized topological Yang-Mills action leads to a twisted N=2 supersymmetric
action. We have found that the R-symmetry of N=2 supersymmetry can be
identified with the flavour symmetry of Dirac-Kahler fermion formulation. Thus
the procedure of twist allows topological ghost fields to be interpreted as the
Dirac-Kahler matter fermions.Comment: 22 pages, LaTe
Serving Rural Asian American and Latino Families and Their Communities: A Call for a Rural Paradigm Shift
The United States rural cultural tapestry continues to be redefined as the country begins a new millennium. In particular, the Asian American and Latino family populations have burgeoned over the last 10 years as the first and second fastest growing populations in the country. This article discusses a working paradigm that illustrates how Extension family consumer scientists and other family specialists can work collectively with rural Asian American and Latino family to promote family and community life
A Nonliearly Dispersive Fifth Order Integrable Equation and its Hierarchy
In this paper, we study the properties of a nonlinearly dispersive integrable
system of fifth order and its associated hierarchy. We describe a Lax
representation for such a system which leads to two infinite series of
conserved charges and two hierarchies of equations that share the same
conserved charges. We construct two compatible Hamiltonian structures as well
as their Casimir functionals. One of the structures has a single Casimir
functional while the other has two. This allows us to extend the flows into
negative order and clarifies the meaning of two different hierarchies of
positive flows. We study the behavior of these systems under a hodograph
transformation and show that they are related to the Kaup-Kupershmidt and the
Sawada-Kotera equations under appropriate Miura transformations. We also
discuss briefly some properties associated with the generalization of second,
third and fourth order Lax operators.Comment: 11 pages, LaTex, version to be published in Journal of Nonlinear
Mathematical Physics, has expanded discussio
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Metabolic syndrome does not affect sustained virologic response of direct-acting antivirals while hepatitis C clearance improves hemoglobin A1c.
AimTo determine whether successful treatment with directacting antivirals (DAA) is associated with improvements in hemoglobin A1c (HbA1c) and if type 2 diabetes mellitus (T2DM) or metabolic syndrome affects sustained virologic response (SVR).MethodsWe performed a retrospective analysis of all hepatitis C virus (HCV) patients at the VA Greater Los Angeles Healthcare System treated with varying DAA therapy between 2014-2016. Separate multivariable logistic regression was performed to determine predictors of HbA1c decrease ≥ 0.5 after DAA treatment and predictors of SVR 12-wk post treatment (SVR12).ResultsA total of 1068 patients were treated with DAA therapy between 2014-2016. The presence of T2DM or metabolic syndrome did not adversely affect SVR12. 106 patients had both HCV and T2DM. Within that cohort, patients who achieved SVR12 had lower mean HbA1c pre treatment (7.35 vs 8.60, P = 0.02), and lower mean HbA1c post-treatment compared to non-responders (6.55 vs 8.61, P = 0.01). The mean reduction in HbA1c after treatment was greater for those who achieved SVR12 than for non-responders (0.79 vs 0.01, P = 0.03). In adjusted models, patients that achieved SVR12 were more likely to have a HbA1c decrease of ≥ 0.5 than those that did not achieve SVR12 (adjusted OR = 7.24, 95%CI: 1.22-42.94).ConclusionIn HCV patients with T2DM, successful treatment with DAA was associated with a significant reduction in HbA1c suggesting that DAA may have a role in improving insulin sensitivity. Furthermore, the presence of T2DM or metabolic syndrome does not adversely affect SVR12 rates in patients treated with DAA
Note on Dirac--K\"ahler massless fields
We obtain the canonical and symmetrical Belinfante energy-momentum tensors of
Dirac--K\"{a}hler's fields. It is shown that the traces of the energy-momentum
tensors are not equal to zero. We find the canonical and Belinfante dilatation
currents which are not conserved, but a new conserved dilatation current is
obtained. It is pointed out that the conformal symmetry is broken. The
canonical quantization is performed and the propagator of the massless fields
in the first-order formalism is found.Comment: 16 pages, minor corrections in the text, published versio
Microscopic analysis of the microscopic reversibility in quantum systems
We investigate the robustness of the microscopic reversibility in open
quantum systems which is discussed by Monnai [arXiv:1106.1982 (2011)]. We
derive an exact relation between the forward transition probability and the
reversed transition probability in the case of a general measurement basis. We
show that the microscopic reversibility acquires some corrections in general
and discuss the physical meaning of the corrections. Under certain processes,
some of the correction terms vanish and we numerically confirmed that the
remaining correction term becomes negligible; the microscopic reversibility
almost holds even when the local system cannot be regarded as macroscopic.Comment: 12 pages, 10 figure
Disorder-induced topological change of the superconducting gap structure in iron pnictides
In superconductors with unconventional pairing mechanisms, the energy gap in
the excitation spectrum often has nodes, which allow quasiparticle excitations
at low energies. In many cases, e.g. -wave cuprate superconductors, the
position and topology of nodes are imposed by the symmetry, and thus the
presence of gapless excitations is protected against disorder. Here we report
on the observation of distinct changes in the gap structure of iron-pnictide
superconductors with increasing impurity scattering. By the successive
introduction of nonmagnetic point defects into BaFe(AsP)
crystals via electron irradiation, we find from the low-temperature penetration
depth measurements that the nodal state changes to a nodeless state with fully
gapped excitations. Moreover, under further irradiation the gapped state
evolves into another gapless state, providing bulk evidence of unconventional
sign-changing -wave superconductivity. This demonstrates that the topology
of the superconducting gap can be controlled by disorder, which is a strikingly
unique feature of iron pnictides.Comment: 5 pages, 4 figure
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