9,495 research outputs found
Surface terms on the Nishimori line of the Gaussian Edwards-Anderson model
For the Edwards-Anderson model we find an integral representation for some
surface terms on the Nishimori line. Among the results are expressions for the
surface pressure for free and periodic boundary conditions and the adjacency
pressure, i.e., the difference between the pressure of a box and the sum of the
pressures of adjacent sub-boxes in which the box can been decomposed. We show
that all those terms indeed behave proportionally to the surface size and prove
the existence in the thermodynamic limit of the adjacency pressure.Comment: Final version with minor corrections. To appear in Journal of
Statistical Physic
The Ising-Sherrington-Kirpatrick model in a magnetic field at high temperature
We study a spin system on a large box with both Ising interaction and
Sherrington-Kirpatrick couplings, in the presence of an external field. Our
results are: (i) existence of the pressure in the limit of an infinite box.
When both Ising and Sherrington-Kirpatrick temperatures are high enough, we
prove that: (ii) the value of the pressure is given by a suitable replica
symmetric solution, and (iii) the fluctuations of the pressure are of order of
the inverse of the square of the volume with a normal distribution in the
limit. In this regime, the pressure can be expressed in terms of random field
Ising models
Desalination effluents and the establishment of the non-indigenous skeleton shrimp Paracaprella pusilla Mayer, 1890 in the south-eastern Mediterranean
A decade long monitoring programme has revealed a flourishing population of the non-indigenous skeleton shrimp Paracaprella pusilla in the vicinity of outfalls of desalination plants off the Mediterranean coast of Israel. The first specimens were collected in 2010, thus predating all previously published records of this species in the Mediterranean Sea. A decade-long disturbance regime related to the construction and operation of the plants may have had a critical role in driving the population growth
Desalination effluents and the establishment of the non-indigenous skeleton shrimp Paracaprella pusilla Mayer, 1890 in the south-eastern Mediterranean
A decade long monitoring programme has revealed a flourishing population of the non-indigenous skeleton shrimp Paracaprella pusilla in the vicinity of outfalls of desalination plants off the Mediterranean coast of Israel. The first specimens were collected in 2010, thus predating all previously published records of this species in the Mediterranean Sea. A decade-long disturbance regime related to the construction and operation of the plants may have had a critical role in driving the population growth
Griffiths Inequalities for Ising Spin Glasses on the Nishimori Line
The Griffiths inequalities for Ising spin glasses are proved on the Nishimori
line with various bond randomness which includes Gaussian and bond
randomness. The proof for Ising systems with Gaussian bond randomness has
already been carried out by Morita et al, which uses not only the gauge theory
but also the properties of the Gaussian distribution, so that it cannot be
directly applied to the systems with other bond randomness. The present proof
essentially uses only the gauge theory, so that it does not depend on the
detail properties of the probability distribution of random interactions. Thus,
the results obtained from the inequalities for Ising systems with Gaussian bond
randomness do also hold for those with various bond randomness, especially with
bond randomness.Comment: 13pages. Submitted to J. Phys. Soc. Jp
Prevalencia del pie plano en niños y niñas en las edades de 9 a 12 años
El objetivo de este estudio, consiste en definir mediante huella plantar, el tipo de pie que se tiene en una escuela primaria con niños de 4º, 5º y 6º, entre las edades de 9 a 12 años. Se les tomo la huella plantar con un tipo de pintura de fácil disolución, para que de esa forma, los niño no tuvieran mayor problema a la hora de limpiarse o lavarse los pies. La cantidad de pie plano, que pensando que se encontraría en mayor cantidad, no lo fue del todo así, se encontraron más pies normales y cavos entre las huellas plantares. Los alumnos de 6º año, arrojaron la mayor cantidad de pie plano, en particular los hombres, las mujeres de 5º grado dieron la mayor cantidad de pie cavo, mientras los hombres de 4º grado arrojaron el mayor tipo de pie normal
Nuclear skin emergence in Skyrme deformed Hartree-Fock calculations
A study of the charge and matter densities and the corresponding rms radii
for even-even isotopes of Ni, Kr, and Sn has been performed in the framework of
deformed self-consistent mean field Skyrme HF+BCS method. The resulting charge
radii and neutron skin thicknesses of these nuclei are compared with available
experimental data, as well as with other theoretical predictions. The formation
of a neutron skin, which manifests itself in an excess of neutrons at distances
greater than the radius of the proton distribution, is analyzed in terms of
various definitions. Formation of a proton skin is shown to be unlikely. The
effects of deformation on the neutron skins in even-even deformed nuclei far
from the stability line are discussed.Comment: 16 pages, 17 figures, to be published in Physical Review
Nuclear Pairing in the T=0 channel revisited
Recent published data on the isoscalar gap in symmetric nuclear matter using
the Paris force and the corresponding BHF single particle dispersion are
corrected leading to an extremely high proton-neutron gap of
MeV at . Arguments whether this value can be reduced due
to screening effects are discussed. A density dependent delta interaction with
cut off is adjusted so as to approximately reproduce the nuclear matter values
with the Paris force.Comment: 4 pages, 4 figure
Replica symmetry breaking in mean field spin glasses trough Hamilton-Jacobi technique
During the last years, through the combined effort of the insight, coming
from physical intuition and computer simulation, and the exploitation of
rigorous mathematical methods, the main features of the mean field
Sherrington-Kirkpatrick spin glass model have been firmly established. In
particular, it has been possible to prove the existence and uniqueness of the
infinite volume limit for the free energy, and its Parisi expression, in terms
of a variational principle, involving a functional order parameter. Even the
expected property of ultrametricity, for the infinite volume states, seems to
be near to a complete proof. The main structural feature of this model, and
related models, is the deep phenomenon of spontaneous replica symmetry breaking
(RSB), discovered by Parisi many years ago. By expanding on our previous work,
the aim of this paper is to investigate a general frame, where replica symmetry
breaking is embedded in a kind of mechanical scheme of the Hamilton-Jacobi
type. Here, the analog of the "time" variable is a parameter characterizing the
strength of the interaction, while the "space" variables rule out
quantitatively the broken replica symmetry pattern. Starting from the simple
cases, where annealing is assumed, or replica symmetry, we build up a
progression of dynamical systems, with an increasing number of space variables,
which allow to weaken the effect of the potential in the Hamilton-Jacobi
equation, as the level of symmetry braking is increased. This new machinery
allows to work out mechanically the general K-step RSB solutions, in a
different interpretation with respect to the replica trick, and lightens easily
their properties as existence or uniqueness.Comment: 24 pages, no figure
Structural Properties of the Disordered Spherical and other Mean Field Spin Models
We extend the approach of Aizenman, Sims and Starr for the SK-type models to
their spherical versions. Such an extension has already been performed for
diluted spin glasses. The factorization property of the optimal structures
found by Guerra for the SK model, which holds for diluted models as well, is
verified also in the case of spherical systems, with the due modifications.
Hence we show that there are some common structural features in various mean
field spin models. These similarities seem to be quite paradigmatic, and we
summarize the various techniques typically used to prove the structural
analogies and to tackle the computation of the free energy per spin in the
thermodynamic limit.Comment: 24 page
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