20,100 research outputs found
Exact Renormalization of Massless QED2
We perform the exact renormalization of two-dimensional massless gauge
theories. Using these exact results we discuss the cluster property and
confinement in both the anomalous and chiral Schwinger models.Comment: 14 pages, no figures, introduction and conclusions modifie
Scaling limit for a drainage network model
We consider the two dimensional version of a drainage network model
introduced by Gangopadhyay, Roy and Sarkar, and show that the appropriately
rescaled family of its paths converges in distribution to the Brownian web. We
do so by verifying the convergence criteria proposed by Fontes, Isopi, Newman
and Ravishankar.Comment: 15 page
Regularity at infinity of real mappings and a Morse-Sard theorem
We prove a new Morse-Sard type theorem for the asymptotic critical values of
semi-algebraic mappings and a new fibration theorem at infinity for
mappings. We show the equivalence of three different types of regularity
conditions which have been used in the literature in order to control the
asymptotic behaviour of mappings. The central role of our picture is played by
the -regularity and its bridge toward the -regularity which implies
topological triviality at infinity
Evading the Few TeV Perturbative Limit in 3-3-1 Models
Some versions of the electroweak SU(3)_L\otimesU(1)_X models cannot be
treated within perturbation theory at energies of few TeV. An extended version
for these models is proposed which is perturbative even at TeV scale posing no
threatening inconsistency for test at future colliders. The extension presented
here needs the addition of three octets of vector leptons, which leave three
new leptonic isotriplets in the SU(2)_L\otimesU(1)_Y subgroup. With this
representation content the running of the electroweak mixing angle, , is such that decreases with the increase of the
energy scale , when only the light states of the Standard Model group are
considered. The neutral exotic gauge boson marks then a new symmetry
frontier.Comment: 15 pages, 2 figures, minor correction
Models for the 3-D axisymmetric gravitational potential of the Milky Way Galaxy - A detailed modelling of the Galactic disk
Aims. Galaxy mass models based on simple and analytical functions for the
density and potential pairs have been widely proposed in the literature. Disk
models constrained by kinematic data alone give information on the global disk
structure only very near the Galactic plane. We attempt to circumvent this
issue by constructing disk mass models whose three-dimensional structures are
constrained by a recent Galactic star counts model in the near-infrared and
also by observations of the hydrogen distribution in the disk. Our main aim is
to provide models for the gravitational potential of the Galaxy that are fully
analytical but also with a more realistic description of the density
distribution in the disk component. Methods. From the disk model directly based
on the observations (here divided into the thin and thick stellar disks and the
HI and H disks subcomponents), we produce fitted mass models by combining
three Miyamoto-Nagai disk profiles of any "model order" (1, 2, or 3) for each
disk subcomponent. The Miyamoto-Nagai disks are combined with models for the
bulge and "dark halo" components and the total set of parameters is adjusted by
observational kinematic constraints. A model which includes a ring density
structure in the disk, beyond the solar Galactic radius, is also investigated.
Results. The Galactic mass models return very good matches to the imposed
observational constraints. In particular, the model with the ring density
structure provides a greater contribution of the disk to the rotational support
inside the solar circle. The gravitational potential models and their
associated force-fields are described in analytically closed forms, and in
addition, they are also compatible with our best knowledge of the stellar and
gas distributions in the disk component. The gravitational potential models are
suited for investigations of orbits in the Galactic disk.Comment: 22 pages, 13 figures, 11 tables, accepted for publication in A&
Mechanism of magnetostructural transformation in multifunctional MnGaC
MnGaC undergoes a ferromagnetic to antiferromagnetic, volume
discontinuous cubic-cubic phase transition as a function of temperature,
pressure and magnetic field. Through a series of temperature dependent x-ray
absorption fine structure spectroscopy experiments at the Mn K and Ga K edge,
it is shown that the first order magnetic transformation in MnGaC is
entirely due to distortions in Mn sub-lattice and with a very little role for
Mn-C interactions. The distortion in Mn sub-lattice results in long and short
Mn-Mn bonds with the longer Mn-Mn bonds favoring ferromagnetic interactions and
the shorter Mn-Mn bonds favoring antiferromagnetic interactions. At the first
order transition, the shorter Mn-Mn bonds exhibit an abrupt decrease in their
length resulting in an antiferromagnetic ground state and a strained lattice.Comment: Accepted in J. Appl. Phys. Please contact authors for supplementary
informatio
Local Runup Amplification By Resonant Wave Interactions
Until now the analysis of long wave runup on a plane beach has been focused
on finding its maximum value, failing to capture the existence of resonant
regimes. One-dimensional numerical simulations in the framework of the
Nonlinear Shallow Water Equations (NSWE) are used to investigate the Boundary
Value Problem (BVP) for plane and non-trivial beaches. Monochromatic waves, as
well as virtual wave-gage recordings from real tsunami simulations, are used as
forcing conditions to the BVP. Resonant phenomena between the incident
wavelength and the beach slope are found to occur, which result in enhanced
runup of non-leading waves. The evolution of energy reveals the existence of a
quasi-periodic state for the case of sinusoidal waves, the energy level of
which, as well as the time required to reach that state, depend on the incident
wavelength for a given beach slope. Dispersion is found to slightly reduce the
value of maximum runup, but not to change the overall picture. Runup
amplification occurs for both leading elevation and depression waves.Comment: 10 pages, 7 Figures. Accepted to Physical Review Letters. Other
author's papers can be downloaded at http://www.lama.univ-savoie.fr/~dutykh
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