10,718 research outputs found
Cooling Effect of the Richtmyer-Meshkov Instability
We provide numerical evidence that the Richtmyer-Meshkov (RM) instability
contributes to the cooling of a relativistic fluid. Due to the presence of jet
particles traveling throughout the medium, shock waves are generated in the
form of Mach cones. The interaction of multiple shock waves can trigger the RM
instability, and we have found that this process leads to a down-cooling of the
relativistic fluid. To confirm the cooling effect of the instability, shock
tube Richtmyer-Meshkov instability simulations are performed. Additionally, in
order to provide an experimental observable of the RM instability resulting
from the Mach cone interaction, we measure the two particle correlation
function and highlight the effects of the interaction. The simulations have
been performed with an improved version of the relativistic lattice Boltzmann
model, including general equations of state and external forces.Comment: 10 pages, 6 figure
Coupled DEM-LBM method for the free-surface simulation of heterogeneous suspensions
The complexity of the interactions between the constituent granular and
liquid phases of a suspension requires an adequate treatment of the
constituents themselves. A promising way for numerical simulations of such
systems is given by hybrid computational frameworks. This is naturally done,
when the Lagrangian description of particle dynamics of the granular phase
finds a correspondence in the fluid description. In this work we employ
extensions of the Lattice-Boltzmann Method for non-Newtonian rheology, free
surfaces, and moving boundaries. The models allows for a full coupling of the
phases, but in a simplified way. An experimental validation is given by an
example of gravity driven flow of a particle suspension
The typology of partial credit guarantee funds around the world
This paper presents data on 76 partial credit guarantee schemes across 46 developed and developing countries. Based on theory, the authors discuss different organizational features of credit guarantee schemes and their variation across countries. They focus on the respective role of government and the private sector and different pricing and risk reduction tools and how they are correlated across countries. The findings show that government has an important role to play in funding and management, but less so in risk assessment and recovery. There is a surprisingly low use of risk-based pricing and limited use of risk management mechanisms.
Quantum Phase Transitions detected by a local probe using Time Correlations and Violations of Leggett-Garg Inequalities
In the present paper we introduce a way of identifying quantum phase
transitions of many-body systems by means of local time correlations and
Leggett-Garg inequalities. This procedure allows to experimentally determine
the quantum critical points not only of finite-order transitions but also those
of infinite order, as the Kosterlitz-Thouless transition that is not always
easy to detect with current methods. By means of simple analytical arguments
for a general spin- Hamiltonian, and matrix product simulations of
one-dimensional and anisotropic models, we argue that
finite-order quantum phase transitions can be determined by singularities of
the time correlations or their derivatives at criticality. The same features
are exhibited by corresponding Leggett-Garg functions, which noticeably
indicate violation of the Leggett-Garg inequalities for early times and all the
Hamiltonian parameters considered. In addition, we find that the infinite-order
transition of the model at the isotropic point can be revealed by the
maximal violation of the Leggett-Garg inequalities. We thus show that quantum
phase transitions can be identified by purely local measurements, and that
many-body systems constitute important candidates to observe experimentally the
violation of Leggett-Garg inequalities.Comment: Minor changes, 11 pages, 11 figures. Final version published in Phys.
Rev.
Exclusive W^+ + photon production in proton-antiproton collisions II: results
We present results for total cross sections, single and double differential
distributions and correlations between pairs of outgoing particles in the
reactions p + antip --> W^+ + photon and p + antip --> W^+ + photon + jet at
sqrt(S)=1.8 TeV. Order alpha-strong QCD corrections and leading logarithm
photon bremsstrahlung contributions are included in the MS-bar mass
factorization scheme for three experimental scenarios: 1) 2-body inclusive
production of W^+ and photon, 2) exclusive production of W^+, photon and 1 jet
and 3) exclusive production of W^+ and photon with 0 jet.
The latest CTEQ parton distribution functions, which fit the newly released
HERA data, are used in our analysis. The dependence of our results on the mass
factorization scale is used to place error bars on our predictions for the
single differential distributions and correlations.Comment: 15 pages (LateX). 50 pages of postscript figures available via ftp
anonymous from max.physics.sunysb.edu in the directory
preprints/mendoza/EXCLUSIVE_W_GAMMA_II.dir (files named fig_*.ps)
ITP-SB-93-80. ([email protected])([email protected]
- …