14,057 research outputs found
Radiation Damping and Quantum Excitation for Longitudinal Charged Particle Dynamics in the Thermal Wave Model
On the basis of the recently proposed {\it Thermal Wave Model (TWM) for
particle beams}, we give a description of the longitudinal charge particle
dynamics in circular accelerating machines by taking into account both
radiation damping and quantum excitation (stochastic effect), in presence of a
RF potential well. The longitudinal dynamics is governed by a 1-D
Schr\"{o}dinger-like equation for a complex wave function whose squared modulus
gives the longitudinal bunch density profile. In this framework, the
appropriate {\it r.m.s. emittance} scaling law, due to the damping effect, is
naturally recovered, and the asymptotic equilibrium condition for the bunch
length, due to the competition between quantum excitation (QE) and radiation
damping (RD), is found. This result opens the possibility to apply the TWM,
already tested for protons, to electrons, for which QE and RD are very
important.Comment: 10 pages, plain LaTeX; published in Phys. Lett. A194 (1994) 113-11
Investigation of the transverse beam dynamics in the thermal wave model with a functional method
We investigated the transverse beam dynamics in a thermal wave model by using
a functional method. It can describe the beam optical elements separately with
a kernel for a component. The method can be applied to general quadrupole
magnets beyond a thin lens approximation as well as drift spaces. We found that
the model can successfully describe the PARMILA simulation result through an
FODO lattice structure for the Gaussian input beam without space charge
effects.Comment: 12 pages, 6 figure
Full Phase-Space Analysis of Particle Beam Transport in the Thermal Wave Model
Within the Thermal Wave Model framework a comparison among Wigner function,
Husimi function, and the phase-space distribution given by a particle tracking
code is made for a particle beam travelling through a linear lens with small
aberrations. The results show that the quantum-like approach seems to be very
promising.Comment: 15 pages, plain LaTeX, + 3 uuencoded figures, to be published in
Phys. Lett.
Geometric phases of water waves
Recently, Banner et al. (2014) highlighted a new fundamental property of open
ocean wave groups, the so-called crest slowdown. For linear narrowband waves,
this is related to the geometric and dynamical phase velocities and
associated with the parallel transport through the principal fiber bundle of
the wave motion with symmetry. The theoretical predictions are
shown to be in fair agreement with ocean field observations, from which the
average crest speed with and
Dimensional Deception from Noncommutative Tori: An alternative to Horava-Lifschitz
We study the dimensional aspect of the geometry of quantum spaces.
Introducing a physically motivated notion of the scaling dimension, we study in
detail the model based on a fuzzy torus. We show that for a natural choice of a
deformed Laplace operator, this model demonstrates quite non-trivial behaviour:
the scaling dimension flows from 2 in IR to 1 in UV. Unlike another model with
the similar property, the so-called Horava-Lifshitz model, our construction
does not have any preferred direction. The dimension flow is rather achieved by
a rearrangement of the degrees of freedom. In this respect the number of
dimensions is deceptive. Some physical consequences are discussed.Comment: 20 pages + extensive appendix. 3 figure
Matrix Bases for Star Products: a Review
We review the matrix bases for a family of noncommutative products
based on a Weyl map. These products include the Moyal product, as well as the
Wick-Voros products and other translation invariant ones. We also review the
derivation of Lie algebra type star products, with adapted matrix bases. We
discuss the uses of these matrix bases for field theory, fuzzy spaces and
emergent gravity
Quantum corrected electron holes
The theory of electron holes is extended into the quantum regime. The
Wigner--Poisson system is solved perturbatively based in lowest order on a
weak, standing electron hole. Quantum corrections are shown to lower the
potential amplitude and to increase the number of deeply trapped electrons.
They, hence, tend to bring this extreme non--equilibrium state closer to
thermodynamic equilibrium, an effect which can be attributed to the tunneling
of particles in this mixed state system.Comment: 12 pages, 3 figure
Projective Systems of Noncommutative Lattices as a Pregeometric Substratum
We present an approximation to topological spaces by {\it noncommutative}
lattices. This approximation has a deep physical flavour based on the
impossibility to fully localize particles in any position measurement. The
original space being approximated is recovered out of a projective limit.Comment: 30 pages, Latex. To appear in `Quantum Groups and Fundamental
Physical Applications', ISI Guccia, Palermo, December 1997, D. Kastler and M.
Rosso Eds., (Nova Science Publishers, USA
Scaling Limits for Multispecies Statistical Mechanics Mean-Field Models
We study the limiting thermodynamic behavior of the normalized sums of spins
in multi-species Curie-Weiss models. We find sufficient conditions for the
limiting random vector to be Gaussian (or to have an exponential distribution
of higher order) and compute the covariance matrix in terms of model
parameters.Comment: 21 page
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