42,535 research outputs found
Transistorized Marx bank pulse circuit provides voltage multiplication with nanosecond rise-time
Base-triggered avalanche transistor circuit used in a Marx bank pulser configuration provides voltage multiplication with nanosecond rise-time. The avalanche-mode transistors replace conventional spark gaps in the Marx bank. The delay time from an input signal to the output signal to the output is typically 6 nanoseconds
Investigation of beauty production and parton shower effects at LHC
We present hadron-level predictions from the Monte Carlo generator Cascade
and parton level calculations of open b quark, b-flavored hadron and inclusive
b-jet production in the framework of the kt-factorization QCD approach for the
LHC energies. The unintegrated gluon densities in a proton are determined using
the CCFM evolution equation and the Kimber-Martin-Ryskin (KMR) prescription.
Our predictions are compared with the first data taken by the CMS and LHCb
collaborations at 7 TeV. We study the theoretical uncertainties of our
calculations and investigate the effects coming from parton showers in initial
and final states. The special role of initial gluon transverse momenta in
description of the data is pointed out.Comment: 19 pages, 11 figures. arXiv admin note: substantial text overlap with
arXiv:1105.507
Z boson production in proton-lead collisions at the LHC accounting for transverse momenta of initial partons
We perform a calculation of inclusive boson production in proton-lead
collisions at the LHC taking into account the transverse momenta of the initial
partons. We use the framework of -factorization combining transverse
momentum dependent parton distributions (TMDs) with off-shell matrix elements.
In order to do it we need to construct appropriate TMDs for lead nuclei which
is done using the parton branching method. Our computations are compared with
data from CMS taken at TeV. The results are in good agreement
with the measurements especially the transverse momentum distribution of the
boson.Comment: 17 pages, 12 figure
Cross-Border M&A Inflows and the Quality of Institutions: A Cross-Country Panel Data Analysis
This paper provides an empirical explanation to the observed disparity in cross-border M&A inflows to developing and developed countries over the last two decades. We show two main results. First, the disparity can be attributed to the difference in the quality of institutions between the two groups of countries. Second, the gain from reforming institutions in developing countries is smaller than that in developed countries. These findings suggest that, with the current speed of institutional reforms in developing countries, the disparity is likely to persist.cross-border M&A inflows, quality of institutions, developing and developed countries, pooled-data and panel data analysis, correlated random effects
HZTool and Rivet: Toolkit and Framework for the Comparison of Simulated Final States and Data at Colliders
A common problem in particle physics is the requirement to reproduce
comparisons between data and theory when the theory is a (general purpose)
Monte Carlo simulation and the data are measurements of final state observables
in high energy collisions. The complexity of the experiments, the obervables
and the models all contribute to making this a highly non-trivial task.
We describe an existing library of Fortran routines, HZTool, which enables,
for each measurement of interest, a comparable prediction to be produced from
any given Monte Carlo generator. The HZTool library is being maintained by
CEDAR, with subroutines for various measurements contributed by a number of
authors within and outside the CEDAR collaboration.
We also describe the outline design and current status of a replacement for
HZTool, to be called Rivet (Robust Independent Validation of Experiment and
Theory). This will use an object-oriented design, implemented in C++, together
with standard interfaces (such as HepMC and AIDA) to make the new framework
more flexible and extensible than the Fortran HZTool.Comment: Contribution to CHEP06 conferenc
Mixed-State Entanglement and Quantum Teleportation through Noisy Channels
The quantum teleportation with noisy EPR state is discussed. Using an optimal
decomposition technique, we compute the concurrence, entanglement of formation
and Groverian measure for various noisy EPR resources. It is shown analytically
that all entanglement measures reduce to zero when , where
is an average fidelity between Alice and Bob. This fact indicates
that the entanglement is a genuine physical resource for the teleportation
process. This fact gives valuable clues on the optimal decomposition for
higher-qubit mixed states. As an example, the optimal decompositions for the
three-qubit mixed states are discussed by adopting a teleportation with W-stateComment: 18 pages, 4 figure
Skyrmion Generation by Current
Skyrmions, once a hypothesized field-theoretical object believed to describe
the nature of elementary particles, became common sightings in recent years
among several non-centrosymmetric metallic ferromagnets. For more practical
applications of Skyrmionic matter as carriers of information, thus realizing
the prospect of "Skyrmionics", it is necessary to have the means to create and
manipulate Skyrmions individually. We show through extensive simulation of the
Landau-Lifshitz-Gilbert equation that a circulating current imparted to the
metallic chiral ferromagnetic system can create isolated Skyrmionic spin
texture without the aid of external magnetic field.Comment: 8 pages, 5 figures, submitted to PR
Spinor Dynamics in an Antiferromagnetic Spin-1 Condensate
We observe coherent spin oscillations in an antiferromagnetic spin-1
Bose-Einstein condensate of sodium. The variation of the spin oscillations with
magnetic field shows a clear signature of nonlinearity, in agreement with
theory, which also predicts anharmonic oscillations near a critical magnetic
field. Measurements of the magnetic phase diagram agree with predictions made
in the approximation of a single spatial mode. The oscillation period yields
the best measurement to date of the sodium spin-dependent interaction
coefficient, determining that the difference between the sodium spin-dependent
s-wave scattering lengths is Bohr radii.Comment: 5 pages, 2 figures. Changes: added reference, minor correction
Tripartite Entanglement in Noninertial Frame
The tripartite entanglement is examined when one of the three parties moves
with a uniform acceleration with respect to other parties. As Unruh effect
indicates, the tripartite entanglement exhibits a decreasing behavior with
increasing the acceleration. Unlike the bipartite entanglement, however, the
tripartite entanglement does not completely vanish in the infinite acceleration
limit. If the three parties, for example, share the Greenberger-Horne-Zeilinger
or W-state initially, the corresponding -tangle, one of the measures for
tripartite entanglement, is shown to be or 0.176 in this
limit, respectively. This fact indicates that the tripartite quantum
information processing may be possible even if one of the parties approaches to
the Rindler horizon. The physical implications of this striking result are
discussed in the context of black hole physics.Comment: 19 pages, 5 figure
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