477 research outputs found
Quantum discord in spin-cluster materials
The total quantum correlation (discord) in Heisenberg dimers is expressed via
the spin-spin correlation function, internal energy, specific heat or magnetic
susceptibility. This allows one to indirectly measure the discord through
neutron scattering, as well as calorimetric or magnetometric experiments. Using
the available experimental data, we found the discord for a number of binuclear
Heisenberg substances with both antiferro- and ferromagnetic interactions. For
the dimerized antiferromagnet copper nitrate Cu(NO_3)_2*2.5H_2O, the three
independent experimental methods named above lead to a discord of approximately
0.2-0.3 bit/dimer at a temperature of 4 K. We also determined the temperature
behavior of discord for hydrated and anhydrous copper acetates, as well as for
the ferromagnetic binuclear copper acetate complex [Cu_2L(OAc)]*6H_2O, where L
is a ligand.Comment: 7 pages, 6 figure
A Lithium Experiment in the Program of Solar Neutrino Research
The experiments sensitive to pp-neutrinos from the Sun are very perspective
for the precise measurement of a mixing angle . A e
scattering experiment (Xmass) and/or a charged-current experiment (the indium
detector) can measure the flux of electron pp-neutrinos. One can find the total
flux of pp-neutrinos from a luminosity constraint after the contribution of
Be and CNO neutrinos to the total luminosity of the Sun are measured. The
radiochemical experiment utilizing a lithium target has the high sensitivity to
the CNO neutrinos, thus, it has a good promise for the precise measurement of a
mixing angle and for the test of a current theory of the evolution of the
stars.Comment: 6 pages, 2 figures, 1 table, A report made by A.Kopylov at
International Conference NANP-2005, June 2005, Dubna, Russi
Lithium Experiment on Solar Neutrinos to Weight the CNO Cycle
The measurement of the flux of beryllium neutrinos with the accuracy of about
10% and CNO neutrinos with the accuracy 30% will enable to find the flux of
pp-neutrinos in the source with the accuracy better than 1% using the
luminosity constraint. The future experiments on \nu e- scattering will enable
to measure with very good accuracy the flux of beryllium and pp-neutrinos on
the Earth. The ratio of the flux of pp-neutrinos on the Earth and in the source
will enable to find with very good accuracy a mixing angle theta solar. Lithium
detector has high sensitivity to CNO neutrinos and can find the contribution of
CNO cycle to the energy generated in the Sun. This will be a stringent test of
the theory of stellar evolution and combined with other experiments will
provide a precise determination of the flux of pp-neutrinos in the source and a
mixing angle theta solar. The work on the development of the technology of
lithium experiment is now in progress.Comment: Minor corrections, one reference added, 11 pages, 2 figures, talk
given at NANP 2003, Dubna, Russia, June 200
Hanbury Brown-Twiss interferometry and second-order correlations of inflaton quanta
The quantum theory of optical coherence is applied to the scrutiny of the
statistical properties of the relic inflaton quanta. After adapting the
description of the quantized scalar and tensor modes of the geometry to the
analysis of intensity correlations, the normalized degrees of first-order and
second-order coherence are computed in the concordance paradigm and are shown
to encode faithfully the statistical properties of the initial quantum state.
The strongly bunched curvature phonons are not only super-Poissonian but also
super-chaotic. Testable inequalities are derived in the limit of large angular
scales and can be physically interpreted in the light of the tenets of Hanbury
Brown-Twiss interferometry. The quantum mechanical results are compared and
contrasted with different situations including the one where intensity
correlations are the result of a classical stochastic process. The survival of
second-order correlations (not necessarily related to the purity of the initial
quantum state) is addressed by defining a generalized ensemble where
super-Poissonian statistics is an intrinsic property of the density matrix and
turns out to be associated with finite volume effects which are expected to
vanish in the thermodynamic limit.Comment: 42 pages, 3 included figures; corrected typos; to appear in Physical
Review
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