23,391 research outputs found
High Temperature Effects on Compactlike Structures
In this work we investigate the transition from kinks to compactons at high
temperatures. We deal with a family of models, described by a real scalar field
with standard kinematics, controlled by a single parameter, real and positive.
The family of models supports kinklike solutions, and the solutions tend to
become compact when the parameter increases to larger and larger values. We
study the one-loop corrections at finite temperature, to see how the thermal
effects add to the effective potential. The results suggest that the symmetry
is restored at very high temperatures.Comment: 6 pages, 4 figures; version to apppear in EPJ
Cosmic voids in modified gravity scenarios
Modified gravity (MG) theories aim to reproduce the observed acceleration of
the Universe by reducing the dark sector while simultaneously recovering
General Relativity (GR) within dense environments. Void studies appear to be a
suitable scenario to search for imprints of alternative gravity models on
cosmological scales. Voids cover an interesting range of density scales where
screening mechanisms fade out, which reaches from a density contrast close to their centers to close to their
boundaries. We present an analysis of the level of distinction between GR and
two modified gravity theories, the Hu-Sawicki and the symmetron theory.
This study relies on the abundance, linear bias, and density profile of voids
detected in n-body cosmological simulations. We define voids as connected
regions made up of the union of spheres with a {\it \textup{mean}} density
given by , but disconnected from any
other voids. We find that the height of void walls is considerably affected by
the gravitational theory, such that it increases for stronger gravity
modifications. Finally, we show that at the level of dark matter n-body
simulations, our constraints allow us to distinguish between GR and MG models
with and . Differences of best-fit values for
MG parameters that are derived independently from multiple void probes may
indicate an incorrect MG model. This serves as an important consistency check.Comment: 15 pages, 12 figure
On the q-deformation of the NJL model
Using a q-deformed fermionic algebra we perform explicitly a deformation of
the Nambu-Jona-Lasinio (NJL) Hamiltonian. In the Bogoliubov-Valatin approach we
obtain the deformed version of the functional for the total energy, which is
minimized to obtain the corresponding gap equation. The breaking of chiral
symmetry and its restoration in the limit are then discussed.Comment: 5 eps figure
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