7,622 research outputs found
Information entropy and nucleon correlations in nuclei
The information entropies in coordinate and momentum spaces and their sum
(, , ) are evaluated for many nuclei using "experimental"
densities or/and momentum distributions. The results are compared with the
harmonic oscillator model and with the short-range correlated distributions. It
is found that depends strongly on and does not depend very much
on the model. The behaviour of is opposite. The various cases we consider
can be classified according to either the quantity of the experimental data we
use or by the values of , i.e., the increase of the quality of the density
and of the momentum distributions leads to an increase of the values of . In
all cases, apart from the linear relation , the linear relation
also holds. V is the mean volume of the nucleus. If is
considered as an ensemble entropy, a relation between or and the
ensemble volume can be found. Finally, comparing different electron scattering
experiments for the same nucleus, it is found that the larger the momentum
transfer ranges, the larger the information entropy is. It is concluded that
could be used to compare different experiments for the same nucleus and to
choose the most reliable one.Comment: 14 pages, 4 figures, 2 table
Statistical Description of Hydrodynamic Processes in Ionic Melts with taking into account Polarization Effects
Statistical description of hydrodynamic processes for ionic melts is proposed
with taking into account polarization effects caused by the deformation of
external ionic shells. This description is carried out by means of the Zubarev
nonequilibrium statistical operator method, appropriate for investigations of
both strong and weak nonequilibrium processes. The nonequilibrium statistical
operator and the generalized hydrodynamic equations that take into account
polarization processes are received for ionic-polarization model of ionic
molten salts when the nonequilibrium averaged values of densities of ions
number, their momentum, dipole momentum and total energy are chosen for the
reduced description parameters. A spectrum of collective excitations is
investigated within the viscoelastic approximation for ion-polarization model
of ionic melts.Comment: 24 pages, RevTex4.1-format, no figure
The Bulk RS KK-gluon at the LHC
We study the possibility of discovering and measuring the properties of the
lightest Kaluza-Klein excitation of the gluon in a Randall-Sundrum scenario
where the Standard Model matter and gauge fields propagate in the bulk. The
KK-gluon decays primarily into top quarks. We discuss how to use the final states to discover and probe the properties of the KK-gluon.
Identification of highly energetic tops is crucial for this analysis. We show
that conventional identification methods relying on well separated decay
products will not work for heavy resonances but suggest alternative methods for
top identification for energetic tops. We find, conservatively, that resonances
with masses less than 5 TeV can be discovered if the algorithm to identify high
tops can reject the QCD background by a factor of 10. We also find that
for similar or lighter masses the spin can be determined and for lighter masses
the chirality of the coupling to can be measured. Since the energetic
top pair final state is a generic signature for a large class of new physics as
the top quark presumably couples most strongly to the electroweak symmetry
breaking sector, the methods we have outlined to study the properties of the
KK-gluon should also be important in other scenarios.Comment: 21 pages, 13 figure
Tree-Independent Dual-Tree Algorithms
Dual-tree algorithms are a widely used class of branch-and-bound algorithms.
Unfortunately, developing dual-tree algorithms for use with different trees and
problems is often complex and burdensome. We introduce a four-part logical
split: the tree, the traversal, the point-to-point base case, and the pruning
rule. We provide a meta-algorithm which allows development of dual-tree
algorithms in a tree-independent manner and easy extension to entirely new
types of trees. Representations are provided for five common algorithms; for
k-nearest neighbor search, this leads to a novel, tighter pruning bound. The
meta-algorithm also allows straightforward extensions to massively parallel
settings.Comment: accepted in ICML 201
Correlations in a two-dimensional Bose gas with long range interactions
We study the correlations of two-dimensional dipolar excitons in coupled
quantum wells with a dipole -- dipole repulsive interaction. We show that at
low concentrations, the Bose degeneracy of the excitons is accompanied by
strong multi-particle correlations and the system behaves as a Bose liquid. At
high concentration the particles interaction suppresses quantum coherence and
the system behaves similar to a classical liquid down to a temperature lower
than typical for a Bose gas. We evaluate the interaction energy per particle
and the resulting blue shift of the exciton luminescence that is a direct tool
to measure the correlations. This theory can apply to other systems of bosons
with extended interaction.Comment: 11 pages including 2 figure
Physical Database Design: A DSS Approach*
This paper presents a working decision support system for use in the physical design of a database. Physical database design, although a structured decision problem, lends itself to a decision support approach because closed form algorithms are computationally infeasible. The paper describes the physical database design problem, presents an overview of a software system for use in solving this problem, and evaluates the use of the system in solving a sample problem
Power, norms and institutional change in the European Union: the protection of the free movement of goods
How do institutions of the European Union change? Using an institutionalist approach, this article highlights the interplay between power, cognitive limits, and the normative order that underpins institutional settings and assesses their impact upon the process of institutional change. Empirical evidence from recent attempts to reinforce the protection of the free movement of goods in the EU suggests that, under conditions of uncertainty, actors with ambiguous preferences assess attempts at institutional change on the basis of the historically defined normative order which holds a given institutional structure together. Hence, path dependent and incremental change occurs even when more ambitious and functionally superior proposals are on offer
True Dielectric and Ideal Conductor in Theory of the Dielectric Function for Coulomb System
On the basis of the exact relations the general formula for the static
dielectric permittivity e(q,0) for Coulomb system is found in the region of
small wave vectors q. The obtained formuladescribes the dielectric function
e(q,0) of the Coulomb system in both states in the "metallic" state and in the
"dielectric" one. The parameter which determines possible states of the Coulomb
system - from the "true" dielectric till the "ideal" conductor is found. The
exact relation for the pair correlation function for two-component system of
electrons and nuclei g_ei(r) is found for the arbitrary thermodynamic
parameters.Comment: 5 pages, no figure
A remark on sphaleron erasure of baryon asymmetry
We complete an existing result for how the baryon asymmetry left over after a
period of full thermal equilibrium depends on different lepton asymmetries.Comment: 5 pages; small clarifications and a reference added; to appear in PR
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