15,989 research outputs found
Reduction of noise in gyro outputs
Technique is described to reduce extraneous gyro output signals by using relatively inexpensive shrouds which do not increase power comsumption. Shrouds reduce noise by minimizing mass of gas spinning with rotor, reducing Reynolds number near rotor, and inducing laminar flow
Local unitary equivalence and entanglement of multipartite pure states
The necessary and sufficient conditions for the equivalence of arbitrary
n-qubit pure quantum states under Local Unitary (LU) operations derived in [B.
Kraus Phys. Rev. Lett. 104, 020504 (2010)] are used to determine the different
LU-equivalence classes of up to five-qubit states. Due to this classification
new parameters characterizing multipartite entanglement are found and their
physical interpretation is given. Moreover, the method is used to derive
examples of two n-qubit states (with n>2 arbitrary) which have the properties
that all the entropies of any subsystem coincide, however, the states are
neither LU-equivalent nor can be mapped into each other by general local
operations and classical communication
Local unitary equivalence of multipartite pure states
Necessary and sufficient conditions for the equivalence of arbitrary n-qubit
pure quantum states under Local Unitary (LU) operations are derived. First, an
easily computable standard form for multipartite states is introduced. Two
generic states are shown to be LU-equivalent iff their standard forms coincide.
The LU-equivalence problem for non--generic states is solved by presenting a
systematic method to determine the LU operators (if they exist) which
interconvert the two states.Comment: 5 page
Measurement of Heavy Quark cross-sections at CDF
The measurement of heavy quark cross-sections provides important tests of the
QCD theory. This paper reviews recent measurements of single b-quark and
correlated b-quark cross-sections at CDF. Two new measurements of the single
b-quark production at CDF agree with the first result from CDF Run II. This
clarifies the experimental situation and confirms the recent agreement of
theoretical prediction with data. A new measurement of the correlated
cross-section with dimuon events at CDF is presented. It agrees with
theory and it does not confirm the anomalously large cross-section
seen in Run I by CDF and D in dimuon events.Comment: EPS HEP2007 conference held in Mancheste
Relaxation to magnetohydrodynamics equilibria via collision brackets
Metriplectic dynamics is applied to compute equilibria of fluid dynamical
systems. The result is a relaxation method in which Hamiltonian dynamics
(symplectic structure) is combined with dissipative mechanisms (metric
structure) that relaxes the system to the desired equilibrium point. The
specific metric operator, which is considered in this work, is formally
analogous to the Landau collision operator. These ideas are illustrated by
means of case studies. The considered physical models are the Euler equations
in vorticity form, the Grad-Shafranov equation, and force-free MHD equilibria.Comment: Conference Proceeding (Theory of Fusions Plasmas, 2018), 9 pages, 8
figure
Particle production in p-p collisions at sqrt(s) = 17 GeV within the statistical model
A thermal-model analysis of particle production of p-p collisions at sqrt(s)
= 17 GeV using the latest available data is presented. The sensitivity of model
parameters on data selections and model assumptions is studied. The system-size
dependence of thermal parameters and recent differences in the statistical
model analysis of p-p collisions at the super proton synchrotron (SPS) are
discussed. It is shown that the temperature and strangeness undersaturation
factor depend strongly on kaon yields which at present are still not well known
experimentally. It is conclude, that within the presently available data at the
SPS it is rather unlikely that the temperature in p-p collisions exceeds
significantly that expected in central collisions of heavy ions at the same
energy.Comment: 6 pages, 3 figures, submitted to Phys. Rev.
Determining topological order from a local ground state correlation function
Topological insulators are physically distinguishable from normal insulators
only near edges and defects, while in the bulk there is no clear signature to
their topological order. In this work we show that the Z index of topological
insulators and the Z index of the integer quantum Hall effect manifest
themselves locally. We do so by providing an algorithm for determining these
indices from a local equal time ground-state correlation function at any
convenient boundary conditions. Our procedure is unaffected by the presence of
disorder and can be naturally generalized to include weak interactions. The
locality of these topological indices implies bulk-edge correspondence theorem.Comment: 7 pages, 3 figures. Major changes: the paper was divided into
sections, the locality of the order in 3D topological insulators is also
discusse
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