6,292 research outputs found
Classical Equations for Quantum Systems
The origin of the phenomenological deterministic laws that approximately
govern the quasiclassical domain of familiar experience is considered in the
context of the quantum mechanics of closed systems such as the universe as a
whole. We investigate the requirements for coarse grainings to yield decoherent
sets of histories that are quasiclassical, i.e. such that the individual
histories obey, with high probability, effective classical equations of motion
interrupted continually by small fluctuations and occasionally by large ones.
We discuss these requirements generally but study them specifically for coarse
grainings of the type that follows a distinguished subset of a complete set of
variables while ignoring the rest. More coarse graining is needed to achieve
decoherence than would be suggested by naive arguments based on the uncertainty
principle. Even coarser graining is required in the distinguished variables for
them to have the necessary inertia to approach classical predictability in the
presence of the noise consisting of the fluctuations that typical mechanisms of
decoherence produce. We describe the derivation of phenomenological equations
of motion explicitly for a particular class of models. Probabilities of the
correlations in time that define equations of motion are explicitly considered.
Fully non-linear cases are studied. Methods are exhibited for finding the form
of the phenomenological equations of motion even when these are only distantly
related to those of the fundamental action. The demonstration of the connection
between quantum-mechanical causality and causalty in classical phenomenological
equations of motion is generalized. The connections among decoherence, noise,
dissipation, and the amount of coarse graining necessary to achieve classical
predictability are investigated quantitatively.Comment: 100pages, 1 figur
The Equivalence Principle in the Non-baryonic Regime
We consider the empirical validity of the equivalence principle for
non-baryonic matter. Working in the context of the TH\epsilon\mu formalism, we
evaluate the constraints experiments place on parameters associated with
violation of the equivalence principle (EVPs) over as wide a sector of the
standard model as possible. Specific examples include new parameter constraints
which arise from torsion balance experiments, gravitational red shift,
variation of the fine structure constant, time-dilation measurements, and
matter/antimatter experiments. We find several new bounds on EVPs in the
leptonic and kaon sectors.Comment: 22 pages, late
Total suspended solids, nutrient and pesticide loads (2014–2015) for rivers that discharge to the Great Barrier Reef
Thermodynamics of d-dimensional charged rotating black brane and AdS/CFT correspondence
We compute the Euclidean actions of a -dimensional charged rotating black
brane both in the canonical and the grand-canonical ensemble through the use of
the counterterms renormalization method, and show that the logarithmic
divergencies associated with the Weyl anomalies and matter field vanish. We
obtain a Smarr-type formula for the mass as a function of the entropy, the
angular momenta, and the electric charge, and show that these quantities
satisfy the first law of thermodynamics. Using the conserved quantities and the
Euclidean actions, we calculate the thermodynamics potentials of the system in
terms of the temperature, angular velocities, and electric potential both in
the canonical and grand-canonical ensembles. We also perform a stability
analysis in these two ensembles, and show that the system is thermally stable.
This is commensurate with the fact that there is no Hawking-Page phase
transition for a black object with zero curvature horizon. Finally, we obtain
the logarithmic correction of the entropy due to the thermal fluctuation around
the equilibrium.Comment: REVTEX4, 15 pages, 1 figur
Identification of the proteins of the yeast U1 small nuclear ribonucleoprotein complex by mass spectrometry
Gauss-Bonnet Black Holes in AdS Spaces
We study thermodynamic properties and phase structures of topological black
holes in Einstein theory with a Gauss-Bonnet term and a negative cosmological
constant. The event horizon of these topological black holes can be a
hypersurface with positive, zero or negative constant curvature. When the
horizon is a zero curvature hypersurface, the thermodynamic properties of black
holes are completely the same as those of black holes without the Gauss-Bonnet
term, although the two black hole solutions are quite different. When the
horizon is a negative constant curvature hypersurface, the thermodynamic
properties of the Gauss-Bonnet black holes are qualitatively similar to those
of black holes without the Gauss-Bonnet term. When the event horizon is a
hypersurface with positive constant curvature, we find that the thermodynamic
properties and phase structures of black holes drastically depend on the
spacetime dimension and the coefficient of the Gauss-Bonnet term: when
, the properties of black hole are also qualitatively similar to the
case without the Gauss-Bonnet term, but when , a new phase of locally
stable small black hole occurs under a critical value of the Gauss-Bonnet
coefficient, and beyond the critical value, the black holes are always
thermodynamically stable. However, the locally stable small black hole is not
globally preferred, instead a thermal anti-de Sitter space is globally
preferred. We find that there is a minimal horizon radius, below which the
Hawking-Page phase transition will not occur since for these black holes the
thermal anti de Sitter space is always globally preferred.Comment: Revtex, 17 pages with 9 eps figures, v2: section II removed and
references added, the version to appear in PR
Gravitational ultrarelativistic spin-orbit interaction and the weak equivalence principle
It is shown that the gravitational ultrarelativistic spin-orbit interaction
violates the weak equivalence principle in the traditional sense. This fact is
a direct consequence of the Mathisson-Papapetrou equations in the frame of
reference comoving with a spinning test particle. The widely held assumption
that the deviation of a spinning test body from a geodesic trajectory is caused
by tidal forces is not correctComment: 12 page
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