2,552 research outputs found
Entanglement dynamics in chaotic systems
We study quantum chaos for systems with more than one degree of freedom, for
which we present an analysis of the dynamics of entanglement. Our analysis
explains the main features of entanglement dynamics and identifies
entanglement-based signatures of quantum chaos. We discuss entanglement
dynamics for a feasible experiment involving an atom in a magneto-optical trap
and compare the results with entanglement dynamics for the well-studied quantum
kicked top.Comment: 4 pages, 6 figure
A first experimental test of de Broglie-Bohm theory against standard quantum mechanics
De Broglie - Bohm (dBB) theory is a deterministic theory, built for
reproducing almost all Quantum Mechanics (QM) predictions, where position plays
the role of a hidden variable. It was recently shown that different coincidence
patterns are predicted by QM and dBB when a double slit experiment is realised
under specific conditions and, therefore, an experiment can test the two
theories. In this letter we present the first realisation of such a double slit
experiment by using correlated photons produced in type I Parametric Down
Conversion. Our results confirm QM contradicting dBB predictions
The effect of Tricresyl-Phosphate (TCP) as an additive on wear of Iron (Fe)
The effect of tricresyl phosphate (TCP) as an antiwear additive in lubricant trimethyol propane triheptanoate (TMPTH) was investigated. The objective was to examine step loading wear by use of surface analysis, wetting, and chemical bonding changes in the lubricant. The investigation consisted of steploading wear studies by a pin or disk tribometer, the effects on wear related to wetting by contact angle and surface tension measurements of various liquid systems, the chemical bonding changes between lubricant and TCP chromatographic analysis, and by determining the reaction between the TCP and metal surfaces through wear scar analysis by Auger emission spectroscopy (AES). The steploading curve for the base fluid alone shows rapid increase of wear rate with load. The steploading curve for the base fluid in presence of 4.25 percent by volume TCP under dry air purge has shown a great reduction of wear rate with all loads studied. It has also been found that the addition of 4.25 percent by volume TCP plus 0.33 percent by volume water to the base lubricant under N2 purge also greatly reduces the wear rate with all loads studied. AES surface analysis reveals a phosphate type wear resistant film, which greatly increases load-bearing capacity, formed on the iron disk. Preliminary chromatographic studies suggest that this film forms either because of ester oxidation or TCP degradation. Wetting studies show direct correlation between the spreading coefficient and the wear rate
Entanglement vs. the quantum-to-classical transition
We analyze the quantum-to-classical transition (QCT) for coupled bipartite
quantum systems for which the position of one of the two subsystems is
continuously monitored. We obtain the surprising result that the QCT can emerge
concomitantly with the presence of highly entangled states in the bipartite
system. Furthermore the changing degree of entanglement is associated with the
back-action of the measurement on the system and is itself an indicator of the
QCT. Our analysis elucidates the role of entanglement in von Neumann's paradigm
of quantum measurements comprised of a system and a monitored measurement
apparatus
Probability for Primordial Black Holes in Multidimensional Universe with Nonlinear Scalar Curvature Terms
We investigate multi-dimensional universe with nonlinear scalar curvature
terms to evaluate the probability of creation of primordial black holes. For
this we obtain Euclidean instanton solution in two different topologies: (a)
- topology which does not accommodate primordial black holes and (b)
-topology which accommodates a pair of black holes. The
probability for quantum creation of an inflationary universe with a pair of
black holes has been evaluated assuming a gravitational action which is
described by a polynomial function of scalar curvature with or without a
cosmological constant () using the framework of semiclassical
approximation of Hartle-Hawking boundary conditions. We discuss here a class of
new gravitational instantons solution in the -theory which are relevant
for cosmological model building.Comment: 18 pages, no figure. accepted in Phys. Rev.
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