29,116 research outputs found
Two-component mixture of charged particles confined in a channel: melting
The melting of a binary system of charged particles confined in a {\it
quasi}-one-dimensional parabolic channel is studied through Monte Carlo
simulations. At zero temperature the particles are ordered in parallel chains.
The melting is anisotropic and different melting temperatures are obtained
according to the spatial direction, and the different types of particles
present in the system. Melting is very different for the single-, two- and
four-chain configurations. A temperature induced structural phase transition is
found between two different four chain ordered states which is absent in the
mono-disperse system. In the mixed regime, where the two types of particles are
only slightly different, melting is almost isotropic and a thermally induced
homogeneous distribution of the distinct types of charges is observed.Comment: To appear in Journal of Physics: condensed matter ; (13 pages, 12
figures
The cosmological behavior of Bekenstein's modified theory of gravity
We study the background cosmology governed by the Tensor-Vector-Scalar theory
of gravity proposed by Bekenstein. We consider a broad family of potentials
that lead to modified gravity and calculate the evolution of the field
variables both numerically and analytically. We find a range of possible
behaviors, from scaling to the late time domination of either the additional
gravitational degrees of freedom or the background fluid.Comment: 10 pages, 8 figures, A few typos corrected in the text and figures.
Version published in PR
Qualitative analysis of a scalar-tensor theory with exponential potential
A qualitative analysis of a scalar-tensor cosmological model, with an
exponential potential for the scalar field, is performed. The phase diagram for
the flat case is constructed. It is shown that solutions with an initial and
final inflationary behaviour appear. The conditions for which the scenario
favored by supernova type Ia observations becomes an attractor in the space of
the solutions are established.Comment: Latex file, 9 pages, 1 figur
Symplectic embeddings into disk cotangent bundles
In this paper, we compute the embedded contact homology (ECH) capacities of
the disk cotangent bundles and . We also find sharp
symplectic embeddings into these domains. In particular, we compute their
Gromov widths. In order to do that, we explicitly calculate the ECH chain
complexes of and using a direct limit argument on
the action inspired by Bourgeois's Morse-Bott approach and ideas from
Nelson-Weiler's work on the ECH of prequantization bundles. Moreover, we use
integrable systems techniques to find explicit symplectic embeddings. In
particular, we prove that the disk cotangent bundles of a hemisphere and of a
punctured sphere are symplectomorphic to an open ball and a symplectic bidisk,
respectively.Comment: 35 page
Effectiveness of Surgery for Lumbar Spinal Stenosis : A Systematic Review and Meta-Analysis
Peer reviewedPublisher PD
- âŠ