12,218 research outputs found
A support property for infinite dimensional interacting diffusion processes
The Dirichlet form associated with the intrinsic gradient on Poisson space is
known to be quasi-regular on the complete metric space
-valued Radon measures on \IR^d\}. We show that under mild conditions,
the set is \e-exceptional, where is the
space of locally finite configurations in \IR^d, that is, measures
satisfying \sup_{x\in\IR^d}\gamma(\{x\})\leq 1. Thus,
the associated diffusion lives on the smaller space . This result also
holds for Gibbs measures with superstable interactions.Comment: French title: Une propri\'et\'e de support pour des processus de
diffusion en dimension infinie avec interactio
The nonlinear evolution of baryonic overdensities in the early universe: Initial conditions of numerical simulations
We run very large cosmological N-body hydrodynamical simulations in order to
study statistically the baryon fractions in early dark matter halos. We
critically examine how differences in the initial conditions affect the gas
fraction in the redshift range z = 11--21. We test three different linear power
spectra for the initial conditions: (1) A complete heating model, which is our
fiducial model; this model follows the evolution of overdensities correctly,
according to Naoz & Barkana (2005), in particular including the spatial
variation of the speed of sound of the gas due to Compton heating from the CMB.
(2) An equal-{\delta} model, which assumes that the initial baryon fluctuations
are equal to those of the dark matter, while conserving sigma8 of the total
matter. (3) A mean cs model, which assumes a uniform speed of sound of the gas.
The latter two models are often used in the literature. We calculate the baryon
fractions for a large sample of halos in our simulations. Our fiducial model
implies that before reionization and significant stellar heating took place,
the minimum mass needed for a minihalo to keep most of its baryons throughout
its formation was ~ 3 * 10^4 Msun. However, the alternative models yield a
wrong (higher by about 50%) minimum mass, since the system retains a memory of
the initial conditions. We also demonstrate this using the "filtering mass"
from linear theory, which accurately describes the evolution of the baryon
fraction throughout the simulated redshift range.Comment: 6 figures 1 table, accepted to MNRA
Neutrino masses and terms in a supersymmetric extra U(1) model
We propose a supersymmetric extra U(1) model, which can generate small
neutrino masses and necessary terms, simultaneously. Fields including
quarks and leptons are embedded in three s of in a different
way among generations. The model has an extra U(1) gauge symmetry at TeV
regions, which has discriminating features from other models studied
previously. Since a neutrino mass matrix induced in the model has a constrained
texture with limited parameters, it can give a prediction. If we impose
neutrino oscillation data to fix those parameters, a value of
can be determined. We also discuss several phenomenological features which are
discriminated from the ones of the MSSM.Comment: 27 pages, 2 figures, final version for publicatio
Torus fibrations and localization of index II
We give a framework of localization for the index of a Dirac-type operator on
an open manifold. Suppose the open manifold has a compact subset whose
complement is covered by a family of finitely many open subsets, each of which
has a structure of the total space of a torus bundle. Under an acyclic
condition we define the index of the Dirac-type operator by using the
Witten-type deformation, and show that the index has several properties, such
as excision property and a product formula. In particular, we show that the
index is localized on the compact set.Comment: 47 pages, 2 figures. To appear in Communications in Mathematical
Physic
Neutron/proton ratio of nucleon emissions as a probe of neutron skin
The dependence between neutron-to-proton yield ratio () and neutron
skin thickness () in neutron-rich projectile induced reactions is
investigated within the framework of the Isospin-Dependent Quantum Molecular
Dynamics (IQMD) model. The density distribution of the Droplet model is
embedded in the initialization of the neutron and proton densities in the
present IQMD model. By adjusting the diffuseness parameter of neutron density
in the Droplet model for the projectile, the relationship between the neutron
skin thickness and the corresponding in the collisions is obtained.
The results show strong linear correlation between and
for neutron-rich Ca and Ni isotopes. It is suggested that may be used
as an experimental observable to extract for neutron-rich nuclei,
which is very significant to the study of the nuclear structure of exotic
nuclei and the equation of state (EOS) of asymmetric nuclear matter.Comment: 7 pages, 5 figures; accepted by Phys. Lett.
Proton-conductive coordination polymer glass for solid-state anhydrous proton batteries
Designing solid-state electrolytes for proton batteries at moderate temperatures is challenging as most solid-state proton conductors suffer from poor moldability and thermal stability. Crystal–glass transformation of coordination polymers (CPs) and metal–organic frameworks (MOFs) via melt-quenching offers diverse accessibility to unique properties as well as processing abilities. Here, we synthesized a glassy-state CP, [Zn₃(H₂PO₄)₆(H₂O)₃](1, 2, 3-benzotriazole), that exhibited a low melting temperature (114 °C) and a high anhydrous single-ion proton conductivity (8.0 × 10⁻³ S cm⁻¹ at 120 °C). Converting crystalline CPs to their glassy-state counterparts via melt-quenching not only initiated an isotropic disordered domain that enhanced H⁺ dynamics, but also generated an immersive interface that was beneficial for solid electrolyte applications. Finally, we demonstrated the first example of a rechargeable all-solid-state H+ battery utilizing the new glassy-state CP, which exhibited a wide operating-temperature range of 25 to 110 °C
Diffusion approximation for equilibrium Kawasaki dynamics in continuum
A Kawasaki dynamics in continuum is a dynamics of an infinite system of
interacting particles in which randomly hop over the space. In
this paper, we deal with an equilibrium Kawasaki dynamics which has a Gibbs
measure as invariant measure. We study a diffusive limit of such a
dynamics, derived through a scaling of both the jump rate and time. Under weak
assumptions on the potential of pair interaction, , (in particular,
admitting a singularity of at zero), we prove that, on a set of smooth
local functions, the generator of the scaled dynamics converges to the
generator of the gradient stochastic dynamics. If the set on which the
generators converge is a core for the diffusion generator, the latter result
implies the weak convergence of finite-dimensional distributions of the
corresponding equilibrium processes. In particular, if the potential is
from and sufficiently quickly converges to zero
at infinity, we conclude the convergence of the processes from a result in
[Choi {\it et al.}, J. Math. Phys. 39 (1998) 6509--6536]
Rho-Nucleon Tensor Coupling and Charge-Exchange Resonances
The Gamow-Teller resonances are discussed in the context of a self-consistent
RPA, based on the relativistic mean field theory. We inquire on the possibility
of substituting the phenomenological Landau-Migdal force by a microscopic
nucleon-nucleon interaction generated from the rho-nucleon tensor coupling. The
effect of this coupling turns out to be very small when the short range
correlations are not taken into account, but too large when these correlations
are simulated by the simple extraction of the contact terms from the resulting
nucleon-nucleon interaction.Comment: 15 pages, LaTeX, 2 figures; extended text, improved figures, new
references added, the version appearing in Phys.Lett.
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