13,771 research outputs found
Single-stage experimental evaluation of boundary layer bleed techniques for high lift stator blades. Part 4 - Data and performance of triple-slotted 0.75 hub diffusion factor stator
Performance tests on slotted hub diffusion factor stator with boundary layer blee
Dynamical invariants and nonadiabatic geometric phases in open quantum systems
We introduce an operational framework to analyze non-adiabatic Abelian and
non-Abelian, cyclic and non-cyclic, geometric phases in open quantum systems.
In order to remove the adiabaticity condition, we generalize the theory of
dynamical invariants to the context of open systems evolving under arbitrary
convolutionless master equations. Geometric phases are then defined through the
Jordan canonical form of the dynamical invariant associated with the
super-operator that governs the master equation. As a by-product, we provide a
sufficient condition for the robustness of the phase against a given decohering
process. We illustrate our results by considering a two-level system in a
Markovian interaction with the environment, where we show that the
non-adiabatic geometric phase acquired by the system can be constructed in such
a way that it is robust against both dephasing and spontaneous emission.Comment: 9 pages, 3 figures. v2: minor corrections and subsection IV.D added.
Published versio
Radical detection in harsh environments by means of laser-induced fluorescence using a single bidirectional optical fiber
A new experimental method is describe enabling detection of hydroxyl radicals (OH) by Laser- Induced Fluorescence (LIF) in high-temperature gasphase reactions. This is accomplished by means of a bidirectional optical fiber probe, which is of interest for applications where optical access is limited. An optical setup has been developed that allows simultaneous excitation and detection of fluorescence using one and the same fiber. Complications resulting from coupling as well as laser-induced scattering are addressed, and different fibers are compared with regard to core material composition and geometric collection efficiency. On this basis a suitable fiber is identified and OH detection and profile measurements are demonstrated in a premixed laminar flame as reference experiment
Quantum Nonlocal Boxes Exhibit Stronger Distillability
The hypothetical nonlocal box (\textsf{NLB}) proposed by Popescu and Rohrlich
allows two spatially separated parties, Alice and Bob, to exhibit stronger than
quantum correlations. If the generated correlations are weak, they can
sometimes be distilled into a stronger correlation by repeated applications of
the \textsf{NLB}. Motivated by the limited distillability of \textsf{NLB}s, we
initiate here a study of the distillation of correlations for nonlocal boxes
that output quantum states rather than classical bits (\textsf{qNLB}s). We
propose a new protocol for distillation and show that it asymptotically
distills a class of correlated quantum nonlocal boxes to the value , whereas in contrast, the optimal non-adaptive
parity protocol for classical nonlocal boxes asymptotically distills only to
the value 3.0. We show that our protocol is an optimal non-adaptive protocol
for 1, 2 and 3 \textsf{qNLB} copies by constructing a matching dual solution
for the associated primal semidefinite program (SDP). We conclude that
\textsf{qNLB}s are a stronger resource for nonlocality than \textsf{NLB}s. The
main premise that develops from this conclusion is that the \textsf{NLB} model
is not the strongest resource to investigate the fundamental principles that
limit quantum nonlocality. As such, our work provides strong motivation to
reconsider the status quo of the principles that are known to limit nonlocal
correlations under the framework of \textsf{qNLB}s rather than \textsf{NLB}s.Comment: 25 pages, 7 figure
Serodiagnosis of infectious mononucleosis by using recombinant Epstein-Barr virus antigens and enzyme-linked immunosorbent assay technology
Four recombinant, diagnostically useful Epstein-Barr virus (EBV) proteins representative of the viral capsid antigen (p150), diffuse early antigen (p54), the major DNA-binding protein (p138), and the EBV nuclear antigen (p72) (W. Hinderer, H. Nebel-Schickel, H.H. Sonneborn, M. Motz, R. Kühbeck, and H. Wolf, J. Exp. Clin. Cancer Res. 7[Suppl.]:132, 1988) were used to set up individual enzyme-linked immunosorbent assays (ELISAs) for the qualitative and quantitative detection of immunoglobulin M (IgM) and IgG antibodies. In direct comparison with results obtained by standard immunofluorescence or immunoperoxidase assays, it was then shown that the recombinant EBV ELISAs provide the means for specific and sensitive serodiagnosis of infectious mononucleosis (IM) caused by EBV. The most useful markers in sera from such patients proved to be IgM antibodies against p54, p138, and p150. Additional positive markers for recent or ongoing IM apparently were IgG antibodies against p54 and p138. In contrast, anti-p72 IgG had a high preference for sera from healthy blood donors and, therefore, can be considered indicative of past exposure to the virus. Altogether, the individual ELISAs proved to be as specific and at least as sensitive for the diagnosis of IM as the currently available standard techniques are. Moreover, our findings suggest that, by combining individual test antigens, a workable ELISA system consisting of three assays (IgM against p54, p138, and p150; IgG against p54 and p138; and IgG against p72) can be established for the standardized rapid diagnosis of acute EBV infections
Mechanisms of alcohol-induced damage to the developing nervous system
Numerous mechanisms likely contribute to the damaging effects of prenatal alcohol exposure on the developing fetus and particularly the developing central nervous system (CNS). The coexistence of a multitude of mechanisms that may act simultaneously or consecutively and differ among various cell types poses particular challenges to researchers. To study alcohol’s effects on the fetus more easily, investigators have used animal models and tissue-culture experiments. Such approaches have identified numerous potential mechanisms through which alcohol acts on the fetus, many of which result in cell death by necrosis or apoptosis. Among these mechanisms are increased oxidative stress, damage to the mitochondria, interference with the activity of growth factors, effects on glia cells, impaired development and function of chemical messenger systems involved in neuronal communication, changes in the transport and uptake of the sugar glucose, effects on cell adhesion, and changes in the regulation of gene activity during development
Spectral Conditions on the State of a Composite Quantum System Implying its Separability
For any unitarily invariant convex function F on the states of a composite
quantum system which isolates the trace there is a critical constant C such
that F(w)<= C for a state w implies that w is not entangled; and for any
possible D > C there are entangled states v with F(v)=D. Upper- and lower
bounds on C are given. The critical values of some F's for qubit/qubit and
qubit/qutrit bipartite systems are computed. Simple conditions on the spectrum
of a state guaranteeing separability are obtained. It is shown that the thermal
equilbrium states specified by any Hamiltonian of an arbitrary compositum are
separable if the temperature is high enough.Comment: Corrects 1. of Lemma 2, and the (under)statement of Proposition 7 of
the earlier version
A statistical investigation of the effects contributed by tape recorders and by wow and flutter of magnetic tape on the accuracy of a telemetry system Technical report no. 15
Effects contributed by tape recorders and by wow and flutter of magnetic tape on accuracy of telemetry syste
The - divergence and Mixing times of quantum Markov processes
We introduce quantum versions of the -divergence, provide a detailed
analysis of their properties, and apply them in the investigation of mixing
times of quantum Markov processes. An approach similar to the one presented in
[1-3] for classical Markov chains is taken to bound the trace-distance from the
steady state of a quantum processes. A strict spectral bound to the convergence
rate can be given for time-discrete as well as for time-continuous quantum
Markov processes. Furthermore the contractive behavior of the
-divergence under the action of a completely positive map is
investigated and contrasted to the contraction of the trace norm. In this
context we analyse different versions of quantum detailed balance and, finally,
give a geometric conductance bound to the convergence rate for unital quantum
Markov processes
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