344,692 research outputs found
DIS Prospects at the Future Muon Collider Facility
We discuss prospects of deep inelastic scattering physics capabilities at the
future muon collider facility. In addition to mu^+ mu^- collider itself, the
facility provides other possibilities. Among the possibilities, we present
muon-proton collider and neutrino fixed target programs at the muon collider
facility. This mu-p collider program extends kinematic reach and luminosity by
an order of magnitude, increasing the possibility of search for new exotic
particles. Perhaps most intriguing DIS prospects come from utilizing high
intensity neutrino beam resulting from continuous decays of muons in various
sections of the muon collider facility. One of the most interesting findings is
a precision measurement of electroweak mixing angle, sin^2theta_W, which can be
achieved to the precision equivalent to delta M_W ~ 30 MeV.Comment: 8 pages, 4 figures, To be published in the proceedings of the 6th
international workshop on Deep Inelastic Scattering, Brussel, Belgium (1998
Assessment criteria for 2D shape transformations in animation
The assessment of 2D shape transformations (or morphing) for animation is a difficult task because it is a multi-dimensional problem. Existing morphing techniques pay most attention to shape information interactive control and mathematical simplicity. This paper shows that it is not enough to use shape information alone, and we should consider other factors such as structure, dynamics, timing, etc. The paper also shows that an overall objective assessment of morphing is impossible because factors such as timing are related to subjective judgement, yet local objective assessment criteria, e.g. based on shape, are available. We propose using “area preservation” as the shape criterion for the 2D case as an acceptable approximation to “volume preservation” in reality, and use it to establish cases in which a number of existing techniques give clearly incorrect results. The possibility of deriving objective assessment criteria for dynamics simulations and timing under certain conditions is discussed
Bayesian analysis of a Tobit quantile regression model
This paper develops a Bayesian framework for Tobit quantile regression. Our approach
is organized around a likelihood function that is based on the asymmetric Laplace dis-
tribution, a choice that turns out to be natural in this context. We discuss families
of prior distribution on the quantile regression vector that lead to proper posterior
distributions with ¯nite moments. We show how the posterior distribution can be
sampled and summarized by Markov chain Monte Carlo methods. A method for com-
paring alternative quantile regression models is also developed and illustrated. The
techniques are illustrated with both simulated and real data. In particular, in an em-
pirical comparison, our approach out-performed two other common classical estimators
Phonon decoherence of quantum entanglement: Robust and fragile states
We study the robustness and fragility of entanglement of open quantum systems
in some exactly solvable models in which the decoherence is caused by a pure
dephasing process. In particular, for the toy models presented in this paper,
we identify two different time scales, one is responsible for local dephasing,
while the other is for entanglement decay. For a class of fragile entangled
states defined in this paper, we find that the entanglement of two qubits, as
measured by concurrence, decays faster asymptotically than the quantum
dephasing of an individual qubit.Comment: 11 pages, revtex, no figure
Scalar products of symmetric functions and matrix integrals
We present relations between Hirota-type bilinear operators, scalar products
on spaces of symmetric functions and integrals defining matrix model partition
functions. Using the fermionic Fock space representation, a proof of the
expansion of an associated class of KP and 2-Toda tau functions in
a series of Schur functions generalizing the hypergeometric series is given and
related to the scalar product formulae. It is shown how special cases of such
-functions may be identified as formal series expansions of partition
functions. A closed form exapnsion of in terms of Schur
functions is derived.Comment: LaTex file. 15 pgs. Based on talks by J. Harnad and A. Yu. Orlov at
the workshop: Nonlinear evolution equations and dynamical systems 2002, Cadiz
(Spain) June 9-16, 2002. To appear in proceedings. (Minor typographical
corrections added, abstract expanded
Singularity points for first passage percolation
Let be fixed scalars. Assign independently to each edge in the
lattice the value with probability or the value with
probability . For all , let denote the first
passage time between and . We show that there are points
such that the ``time constant'' in the direction of ,
namely, is not a three
times differentiable function of .Comment: Published at http://dx.doi.org/10.1214/009117905000000819 in the
Annals of Probability (http://www.imstat.org/aop/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Coherent State Control of Non-Interacting Quantum Entanglement
We exploit a novel approximation scheme to obtain a new and compact formula
for the parameters underlying coherent-state control of the evolution of a pair
of entangled two-level systems. It is appropriate for long times and for
relatively strong external quantum control via coherent state irradiation. We
take account of both discrete-state and continuous-variable degrees of freedom.
The formula predicts the relative heights of entanglement revivals and their
timing and duration.Comment: Published in PRA, 10 pages, 7 figure
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