238 research outputs found
Projections of the population size of Russia and the world
The article presents forecasts of the population of Russia and the world in General. Highlighting three variants of the forecast of a demographic situation in Russia before 2050 yr. The article presents a forecast change in population by category (male, female, able-bodied population). It is concluded that the main growth of the population to 2050 yr. will be at the expense of labour migration, primarily from CIS countries. The analysis of trends in population to 2050 yr. in different countries and continents as a whole. Presents the forecasted share of elderly population of the continents of the world in 2050 yr. conclusions about the population decline of the highly developed European countries, and the increase in the number of developing
Projections of the population size of Russia and the world
The article presents forecasts of the population of Russia and the world in General. Highlighting three variants of the forecast of a demographic situation in Russia before 2050 yr. The article presents a forecast change in population by category (male, female, able-bodied population). It is concluded that the main growth of the population to 2050 yr. will be at the expense of labour migration, primarily from CIS countries. The analysis of trends in population to 2050 yr. in different countries and continents as a whole. Presents the forecasted share of elderly population of the continents of the world in 2050 yr. conclusions about the population decline of the highly developed European countries, and the increase in the number of developing
Atomic population distribution in the output ports of cold-atom interferometers with optical splitting and recombination
Cold-atom interferometers with optical splitting and recombination use
off-resonant laser beams to split a cloud of Bose-Einstein condensate (BEC)
into two clouds that travel along different paths and are then recombined again
using optical beams. After the recombination, the BEC in general populates both
the cloud at rest and the moving clouds. Measuring relative number of atoms in
each of these clouds yields information about the relative phase shift
accumulated by the atoms in the two moving clouds during the interferometric
cycle. We derive the expression for the probability of finding any given number
of atoms in each of the clouds, discuss features of the probability density
distribution, analyze its dependence on the relative accumulated phase shift as
a function of the strength of the interatomic interactions, and compare our
results with experiment.Comment: 25 pages, 7 figure
Particle Number Fluctuations in the Microcanonical Ensemble
Particle number fluctuations are studied in the microcanonical ensemble. For
the Boltzmann statistics we deduce exact analytical formulae for the
microcanonical partition functions in the case of non-interacting massless
neutral particles and charged particles with zero net charge. The particle
number fluctuations are calculated and we find that in the microcanonical
ensemble they are suppressed in comparison to the fluctuations in the canonical
and grand canonical ensembles. This remains valid in the thermodynamic limit
too, so that the well-known equivalence of all statistical ensembles refers to
average quantities, but does not apply to fluctuations. In the thermodynamic
limit we are able to calculate the particle number fluctuations in the system
of massive bosons and fermions when the exact conservation laws of both the
energy and charge are taken into account.Comment: REVTeX, 17 pages, 9 figures, v3: misprints a correcte
Theoretical analysis of a single and double reflection atom interferometer in a weakly-confining magnetic trap
The operation of a BEC based atom interferometer, where the atoms are held in
a weakly-confining magnetic trap and manipulated with counter-propagating laser
beams, is analyzed. A simple analytic model is developed to describe the
dynamics of the interferometer. It is used to find the regions of parameter
space with high and low contrast of the interference fringes for both single
and double reflection interferometers. We demonstrate that for a double
reflection interferometer the coherence time can be increased by shifting the
recombination time. The theory is compared with recent experimental
realizations of these interferometers.Comment: 25 pages, 6 figure
Particle Number Fluctuations in Statistical Model with Exact Charge Conservation Laws
Even though the first momenta i.e. the ensemble average quantities in
canonical ensemble (CE) give the grand canonical (GC) results in large
multiplicity limit, the fluctuations involving second moments do not respect
this asymptotic behaviour. Instead, the asymptotics are strikingly different,
giving a new handle in study of statistical particle number fluctuations in
relativistic nuclear reactions. Here we study the analytical large volume
asymptotics to general case of multispecies hadron gas carrying fixed baryon
number, strangeness and electric charge. By means of Monte Carlo simulations we
have also studied the general multiplicity probability distributions taking
into account the decay chains of resonance states.Comment: 4 pages, 2 figures. The report of the talk given in Strangeness in
Quark Matter 2004, Cape Town. Submitted to J. Phys. G: Nucl. Part. Phy
Multiplicity Fluctuations in Hadron-Resonance Gas
The charged hadron multiplicity fluctuations are considered in the canonical
ensemble. The microscopic correlator method is extended to include three
conserved charges: baryon number, electric charge and strangeness. The
analytical formulae are presented that allow to include resonance decay
contributions to correlations and fluctuations. We make the predictions for the
scaled variances of negative, positive and all charged hadrons in the most
central Pb+Pb (Au+Au) collisions for different collision energies from SIS and
AGS to SPS and RHIC.Comment: 19 pages, 4 figure
Entanglement Entropy in the Calogero-Sutherland Model
We investigate the entanglement entropy between two subsets of particles in
the ground state of the Calogero-Sutherland model. By using the duality
relations of the Jack symmetric polynomials, we obtain exact expressions for
both the reduced density matrix and the entanglement entropy in the limit of an
infinite number of particles traced out. From these results, we obtain an upper
bound value of the entanglement entropy. This upper bound has a clear
interpretation in terms of fractional exclusion statistics.Comment: 14 pages, 3figures, references adde
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