15,268 research outputs found
Generalised Fractional Evolution Equations of Caputo Type
This paper is devoted to the study of generalised time-fractional evolution
equations involving Caputo type derivatives. Using analytical methods and
probabilistic arguments we obtain well-posedness results and stochastic
representations for the solutions. These results encompass known linear and
non-linear equations from classical fractional partial differential equations
such as the time-space-fractional diffusion equation, as well as their far
reaching extensions. \\ Meaning is given to a probabilistic generalisation of
Mittag-Leffler functions.Comment: To be published in 'Chaos, Solitons & Fractals
Topological gravitation on graph manifolds
A model of topological field theory is presented in which the vacuum coupling
constants are topological invariants of the four-dimensional spacetime. Thus
the coupling constants are theoretically computable, and they indicate the
topological structure of our universe.Comment: 3 pages, a talk delivered at the 11th Marcel Grossmann Meeting (2006
Anomalous quartic couplings in collisions at the LHeC and the FCC-he
We conducted a study on measuring production and on the sensitivity
limits at Confidence Level on thirteen anomalous couplings obtained by
dimension-8 operators which are related to the anomalous quartic
couplings. We consider the main reaction with the sub-process at
the Large Hadron electron Collider (LHeC) and the Future Circular
Collider-hadron electron (FCC-he). For the LHeC, energies of the beams
are taken to be and 140 GeV and the energy of the beams is taken
to be TeV. For the FCC-he, energies of the beams are taken to
be and 140 GeV and the energy of the beams is taken to be TeV, respectively. It is interesting to notice that the LHeC and the FCC-he
will lead to model-independent limits on the anomalous quartic
couplings which are one order of magnitude stringent than the CMS Collaboration
limits, in addition to being competitive with other limits reported in the
literature.Comment: 28 pages, 10 Figures and 13 Table
La escuela digital: análisis de las representaciones y prácticas de los actores educativos ante los materiales didácticos en la Red
Spectral properties of finite laser-driven lattices of ultracold Rydberg atoms
We investigate the spectral properties of a finite laser-driven lattice of
ultracold Rydberg atoms exploiting the dipole blockade effect in the frozen
Rydberg gas regime. Uniform one-dimensional lattices as well as lattices with
variable spacings are considered. In the case of a weak laser coupling, we find
a multitude of many-body Rydberg states with well-defined excitation properties
which are adiabatically accessible starting from the ground state. A
comprehensive analysis of the degeneracies of the spectrum as well as of the
single and pair excitations numbers of the eigenstates is performed. In the
strong laser regime, analytical solutions for the pseudo-fermionic eigenmodes
are derived. Perturbative energy corrections for this approximative approach
are provided.Comment: 17 pages, 12 figure
Order reductions of Lorentz-Dirac-like equations
We discuss the phenomenon of preacceleration in the light of a method of
successive approximations used to construct the physical order reduction of a
large class of singular equations. A simple but illustrative physical example
is analyzed to get more insight into the convergence properties of the method.Comment: 6 pages, LaTeX, IOP macros, no figure
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