45,726 research outputs found
On the Two Obstacles Problem in Orlicz-Sobolev Spaces and Applications
We prove the Lewy-Stampacchia inequalities for the two obstacles problem in
abstract form for T-monotone operators. As a consequence for a general class of
quasi-linear elliptic operators of Ladyzhenskaya-Uraltseva type, including
p(x)-Laplacian type operators, we derive new results of
regularity for the solution. We also apply those inequalities to obtain new
results to the N-membranes problem and the regularity and monotonicity
properties to obtain the existence of a solution to a quasi-variational problem
in (generalized) Orlicz-Sobolev spaces
Marinari-Parisi and Supersymmetric Collective Field Theory
A field theoretic formulation of the Marinari-Parisi supersymmetric matrix
model is established and shown to be equivalent to a recently proposed
supersymmetrization of the bosonic collective string field theory. It also
corresponds to a continuum description of super-Calogero models. The
perturbation theory of the model is developed and, in this approach, an
infinite sequence of vertices is generated. A class of potentials is identified
for which the spectrum is that of a massless boson and Majorana fermion. For
the harmonic oscillator case, the cubic vertices are obtained in an oscillator
basis. For a rather general class of potentials it is argued that one cannot
generate from Marinari-Parisi models a continuum limit similar to that of the
d=1 bosonic string.Comment: 45 page
Modelling distribution functions and fragmentation functions
We present examples for the calculation of the distribution and fragmentation
functions using the representation in terms of non-local matrix elements of
quark field operators. As specific examples, we use a simple spectator model to
estimate the leading twist quark distribution functions and the fragmentation
functions for a quark into a nucleon or a pion.Comment: 5 pages RevTeX, talk presented at the First ELFE School on
Confinement Physics, 22-28 July 1995, Cambridge, Englan
Impact of misalignments on the analysis of B decays
This note investigates the effects of a misaligned tracking system on the
analysis of B decays. Misalignment effects of both the vertex locator and the
inner and outer T-stations have been studied. -scaling effects of the vertex
locator are also considered. It is proven that misalignments of the order of
the detector single-hit resolutions have little or negligible effects on the
quality of the reconstruction and of the analysis of B decays. The studies were
performed with a sample of decays, but the impact of
misalignments on the performance of the pattern recognition algorithms and on
the primary vertex resolutions, assessed for the first time, are rather general
and not restricted to decays
Collapse transition in polymer models with multiple monomers per site and multiple bonds per edge
We present results from extensive Monte Carlo simulations of polymer models
where each lattice site can be visited by up to monomers and no restriction
is imposed on the number of bonds on each lattice edge. These \textit{multiple
monomer per site} (MMS) models are investigated on the square and cubic
lattices, for and , by associating Boltzmann weights ,
and to sites visited by 1, 2 and
3 monomers, respectively. Two versions of the MMS models are considered for
which immediate reversals of the walks are allowed (RA) or forbidden (RF). In
contrast to previous simulations of these models, we find the same
thermodynamic behavior for both RA and RF versions. In three-dimensions, the
phase diagrams - in space - are featured by coil and
globule phases separated by a line of points, as thoroughly
demonstrated by the metric , crossover and entropic
exponents. The existence of the -lines is also confirmed by the second
virial coefficient. This shows that no discontinuous collapse transition exists
in these models, in contrast to previous claims based on a weak bimodality
observed in some distributions, which indeed exists in a narrow region very
close to the -line when . Interestingly, in
two-dimensions, only a crossover is found between the coil and globule phases
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