9,632 research outputs found
Estimates of Private Sector Wealth
This paper provides quarterly estimates of private non-human wealth at market prices in Australia over the past decade. These estimates are based on the methodology set out in Piggott (1987), although improvements have been made in several important areas. The estimates suggest that private non-human wealth stood at $1,428 billion in the June quarter 1990. The dwelling stock accounted for 52 per cent of the total, business assets for 37 per cent, with the remainder being made up of consumer durables, holdings of government bonds and holdings of currency. The paper also introduces an index of asset prices, based on the wealth estimates.
Quantum fluctuation-dissipation theorem: a time domain formulation
A time-domain formulation of the equilibrium quantum fluctuation-dissipation
theorem (FDT) in the whole range of temperatures is presented. In the classical
limit, the FDT establishes a proportionality relation between the dissipative
part of the linear response function and the derivative of the corresponding
equilibrium correlation function. At zero temperature, the FDT takes the form
of Hilbert transform relations between the dissipative part of the response
function and the corresponding symmetrized equilibrium correlation function,
which allows to establish a connection with analytic signal theory. The
time-domain formulation of the FDT is especially valuable when
out-of-equilibrium dynamics is concerned, as it is for instance the case in the
discussion of aging phenomena.Comment: 18 TeX pages, 1 Postscript figure, submitted to Physica
Study of multiple hologram recording in lithium niobate
The results of detailed experimental and theoretical considerations relating to multiple hologram recording in lithium niobate are reported. The following problem areas are identified and discussed: (1) the angular selectivity of the stored holograms, (2) interference effects due to the crystal surfaces, (3) beam divergence effects, (4) material recording sensitivity, and (5) scattered light from material inhomogeneities
Thermodynamics of a classical ideal gas at arbitrary temperatures
We propose a fundamental relation for a classical ideal gas that is valid at
all temperatures with remarkable accuracy. All thermodynamical properties of
classical ideal gases can be deduced from this relation at arbitrary
temperature.Comment: 7 pages, Latex, with 2 additional files for pslatex figures.
Expression for entropy added in the 2nd versio
Theory for the reduction of products of spin operators
In this study we show that the sum of the powers of arbitrary products of
quantum spin operators such as can be reduced by one
unit, if this sum is equal to 2S+1, S being the spin quantum number. We
emphasize that by a repeated application of this procedure \em all \em
arbitrary spin operator products with a sum of powers larger than 2S can be
replaced by a combination of spin operators with a maximum sum of powers not
larger than 2S. This transformation is exact. All spin operators must belong to
the same lattice site. By use of this procedure the consideration of single-ion
anisotropies and the investigation of the magnetic reorientation within a
Green's function theory are facilitated. Furthermore, it may be useful for the
study of time dependent magnetic properties within the ultrashort (fsec) time
domain.Comment: 11 pages, 1 table, uses rotatin
Josephson junctions and dark energy
In a recent paper Beck and Mackey [astro-ph/0603397] argue that the argument
we gave in our paper [Phys. Lett. B 606, 77 (2005)] to disprove their claim
that dark energy can be discovered in the Lab through noise measurements of
Josephson junctions is incorrect. In particular, they emphasize that the
measured noise spectrum in Josephson junctions is a consequence of the
fluctuation dissipation theorem, while our argument was based on equilibrium
statistical mechanics. In this note we show that the fluctuation dissipation
relation does not depend upon any shift of vacuum (zero-point) energies, and
therefore, as already concluded in our previous paper, dark energy has nothing
to do with the proposed measurements.Comment: 4 page
Introduction to Quantum Thermodynamics: History and Prospects
Quantum Thermodynamics is a continuous dialogue between two independent
theories: Thermodynamics and Quantum Mechanics. Whenever the two theories
addressed the same phenomena new insight has emerged. We follow the dialogue
from equilibrium Quantum Thermodynamics and the notion of entropy and entropy
inequalities which are the base of the II-law. Dynamical considerations lead to
non-equilibrium thermodynamics of quantum Open Systems. The central part played
by completely positive maps is discussed leading to the
Gorini-Kossakowski-Lindblad-Sudarshan GKLS equation. We address the connection
to thermodynamics through the system-bath weak-coupling-limit WCL leading to
dynamical versions of the I-law. The dialogue has developed through the
analysis of quantum engines and refrigerators. Reciprocating and continuous
engines are discussed. The autonomous quantum absorption refrigerator is
employed to illustrate the III-law. Finally, we describe some open questions
and perspectives
The Atmosphere Explorer power subsystem
The design and operation of the power subsystem for the Atmospheric Explorer spacecraft are discussed. The additional functional redundancy which was added in several component areas to improve the overall subsystem reliability is analyzed. The battery charging technique has been modified to include third electrode overcharge control. The automatic removal of all battery charge is provided to correct abnormally high battery voltages. An undervoltage detector has been added which removes all nonessential spacecraft loads when the battery voltage falls below a given level. All automatic functions can be over-ridden by ground command
Rheology of Granular Materials: Dynamics in a Stress Landscape
We present a framework for analyzing the rheology of dense driven granular
materials, based on a recent proposal of a stress-based ensemble. In this
ensemble fluctuations in a granular system near jamming are controlled by a
temperature-like parameter, the angoricity, which is conjugate to the stress of
the system. In this paper, we develop a model for slowly driven granular
materials based on the stress ensemble and the idea of a landscape in stress
space. The idea of an activated process driven by the angoricity has been shown
by Behringer et al (2008) to describe the logarithmic strengthening of granular
materials. Just as in the Soft Glassy Rheology (SGR) picture, our model
represents the evolution of a small patch of granular material (a mesoscopic
region) in a stress-based trap landscape. The angoricity plays the role of the
fluctuation temperature in SGR. We determine (a) the constitutive equation, (b)
the yield stress, and (c) the distribution of stress dissipated during granular
shearing experiments, and compare these predictions to experiments of Hartley &
Behringer (2003).Comment: 17 pages, 4 figure
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