60,676 research outputs found
The concentration-compactness principle for variable exponent spaces and applications
In this paper we extend the well-known concentration -- compactness principle
of P.L. Lions to the variable exponent case. We also give some applications to
the existence problem for the Laplacian with critical growth
Pairing Correlations in Finite Systems: From the weak to the strong fluctuations regime
The Particle Number Projected Generator Coordinate Method is formulated for
the pairing Hamiltonian in a detailed way in the projection after variation and
the variation after projection methods. The dependence of the wave functions on
the generator coordinate is analyzed performing numerical applications for the
most relevant collective coordinates. The calculations reproduce the exact
solution in the weak, crossover and strong pairing regimes. The physical
insight of the Ansatz and its numerical simplicity make this theory an
excellent tool to study pairing correlations in complex situations and/or
involved Hamiltonians.Comment: Submitted to EPJ
A multiquark description of the and
Within a theoretical framework that accounts for all open-charm mesons,
including the , the and the , we
analyze the structure and explore possible quantum number assignments for the
and the mesons reported by BABAR and Belle
Collaborations. The open-charm sector is properly described if considered as a
combination of conventional quark-antiquark states and four--quark components.
All negative parity and states can be understood in terms only of components, however the description of the and mesons is
improved whenever the mixing between two-- and four--quarks configurations is
included. We analyze all possible quantum number assignments for the
in terms of both and configurations.
We discuss the role played by the electromagnetic and strong decay widths as
basic tools to distinguish among them. The broad structure reported by BABAR
near 2.7 GeV is also analyzed.Comment: 10 pages, 5 table
Constituent quark model study of the meson spectra
The spectrum is studied in a generalized constituent quark model
constrained in the study of the phenomenology and the baryon spectrum. An
overall good fit to the available experimental data is obtained. A detailed
analysis of all sectors from the light-pseudoscalar and vector mesons to
bottomonium is performed paying special attention to the existence and nature
of some non well-established states. These results should serve as a
complementary tool in distinguishing conventional quark model mesons from
glueballs, hybrids or multiquark states.Comment: 34 pages, 2 figures. Revised version accepted for publication in J.
Phys.
convergence result for nonlocal elliptic-type problems via Tartar's method
In this work we obtain a compactness result for the convergence of a
family of nonlocal and nonlinear monotone elliptic-type problems by means of
Tartar's method of oscillating test functions.Comment: In this revision we added a new section that shows the
Gamma-convergence of the associated energy functional
Adsorption preference reversal phenomenon from multisite-occupancy theory fortwo-dimensional lattices
The statistical thermodynamics of polyatomic species mixtures adsorbed on
two-dimensional substrates was developed on a generalization in the spirit of
the lattice-gas model and the classical Guggenheim-DiMarzio approximation. In
this scheme, the coverage and temperature dependence of the Helmholtz free
energy and chemical potential are given. The formalism leads to the exact
statistical thermodynamics of binary mixtures adsorbed in one dimension,
provides a close approximation for two-dimensional systems accounting multisite
occupancy and allows to discuss the dimensionality and lattice structure
effects on the known phenomenon of adsorption preference reversal.Comment: 13 pages, 4 figure
Contractions from to the M-theory superalgebra extended by additional fermionic generators
We study here the generalized Weimar-Woods contractions of the superalgebra
in order to obtain a suitable algebra that could
describe the gauge group of supergravity. The contracted superalgebras
are assumed to be given in terms of fermionic extensions of the M-theory
superalgebra. We show that the only superalgebra of this type obtained by
contraction is the only one for which the three-form of supergravity
cannot be trivialized. Therefore, supergravity cannot be connected in
this way with a contraction of
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