1,230 research outputs found
Particle-wave duality: a dichotomy between symmetry and asymmetry
Symmetry plays a central role in many areas of modern physics. Here we show
that it also underpins the dual particle and wave nature of quantum systems. We
begin by noting that a classical point particle breaks translational symmetry
whereas a wave with uniform amplitude does not. This provides a basis for
associating particle nature with asymmetry and wave nature with symmetry. We
derive expressions for the maximum amount of classical information we can have
about the symmetry and asymmetry of a quantum system with respect to an
arbitrary group. We find that the sum of the information about the symmetry
(wave nature) and the asymmetry (particle nature) is bounded by log(D) where D
is the dimension of the Hilbert space. The combination of multiple systems is
shown to exhibit greater symmetry and thus more wavelike character. In
particular, a class of entangled systems is shown to be capable of exhibiting
wave-like symmetry as a whole while exhibiting particle-like asymmetry
internally. We also show that superdense coding can be viewed as being
essentially an interference phenomenon involving wave-like symmetry with
respect to the group of Pauli operators.Comment: 20 pages, 3 figure
A Testable Solution of the Cosmological Constant and Coincidence Problems
We present a new solution to the cosmological constant (CC) and coincidence
problems in which the observed value of the CC, , is linked to other
observable properties of the universe. This is achieved by promoting the CC
from a parameter which must to specified, to a field which can take many
possible values. The observed value of Lambda ~ 1/(9.3 Gyrs)^2\Lambda$-values
and does not rely on anthropic selection effects. Our model includes no
unnatural small parameters and does not require the introduction of new
dynamical scalar fields or modifications to general relativity, and it can be
tested by astronomical observations in the near future.Comment: 31 pages, 4 figures; v2: version accepted by Phys. Rev.
Coal - Issues for the Eighties
This paper summarizes the proceedings of the inaugural meeting to establish a new international collaborative project for the coal industry -- the first IIASA Industry Study to be carried out under the generic title of "Issues for the Eighties". The purpose of this paper is to provide information for those who may be interested in the project to understand what has so far been done, and what the value may be of cooperation.
It may be worth saying something about the general concept lying behind the IIASA Industry Studies. The purpose of these is to bring together representatives of the same industry from many countries, to identify the key issues which the industry faces over the next ten years, to identify the way in which systems analysis can assist in the major policy and investment decisions, and to engage in a collaborative program of information exchange and research. IIASA's role is essentially catalytic. It is our task to identify needs, and seek to create the conditions in which they can be satisfied. Its unique international -- but nongovernmental -- position in the systems analysis field, and the fact that it works in so many fields of concern to industry (Energy, Resources, Environment, Manpower and Health, Management, Technology, etc.,) makes it an ideal base for a creative exchange of information methods and ideas. Funding limitations restrict the amount of research that it can undertake but, in any case, the knowledge and research skills lie within the industry itself. The fact that the work will be collaborative is fundamental to its success, which we hope will result in better information and an improved methodology for those involved in policy decisions.
Up to the present, two such industry studies have been set in motion, one in coal and another in the forestry/forest product industry. The reasons for selecting the coal industry, and the general background to the study, are set out in Appendix A which was sent out in advance to participants at the inaugural meeting held at IIASA in March 1979. A brief report of that meeting, together with recommendations for future action follow. Various supporting documents are set out in the Appendices
A Way to Dynamically Overcome the Cosmological Constant Problem
The Cosmological Constant problem can be solved once we require that the full
standard Einstein Hilbert lagrangian, gravity plus matter, is multiplied by a
total derivative. We analyze such a picture writing the total derivative as the
covariant gradient of a new vector field (b_mu). The dynamics of this b_mu
field can play a key role in the explanation of the present cosmological
acceleration of the Universe.Comment: 5 page
Schwarzschild and Synge once again
We complete the historical overview about the geometry of a Schwarzschild
black hole at its horizon by emphasizing the contribution made by J. L. Synge
in 1950 to its clarification.Comment: 2 pages, LaTeX, submitted for publication; 2 references, one Note,
and an Acknowledgement are adde
Direct Detection Rates of Dark Matter Coupled to Dark Energy
We investigate the effect of a coupling between dark matter and dark energy
on the rates for the direct detection of dark matter. The magnitude of the
effect depends on the strength of this new interaction relative to
gravity. The resulting isothermal velocity distribution for dark matter in
galaxy halos is still Maxwell-Boltzmann (M-B), but the characteristic velocity
and the escape velocity are increased by . We adopt a
phenomenological approach and consider values of near unity. For such
values we find that: (i) The (time averaged) event rate increases for light
WIMPs, while it is somewhat reduced for WIMP masses larger than 100 GeV. (ii)
The time dependence of the rate arising from the modulation amplitude is
decreased compared to the standard M-B velocity distribution. (iii) The average
and maximum WIMP energy increase proportionally to , which, for
sufficiently massive WIMPs, allows the possibility of designing experiments
measuring rays following nuclear de-excitation.Comment: 16 pages, 7 figure
Direct Dark Matter Detection with Velocity Distribution in the Eddington approach
Exotic dark matter together with the vacuum energy (associated with the
cosmological constant) seem to dominate the Universe. Thus its direct detection
is central to particle physics and cosmology. Supersymmetry provides a natural
dark matter candidate, the lightest supersymmetric particle (LSP). One
essential ingredient in obtaining the direct detection rates is the density and
the velocity distribution of the LSP in our vicinity. In the present paper we
study simultaneously density profiles and velocity distributions in the context
of the Eddington approach. In such an approach, unlike the commonly assumed
Maxwell-Boltzmann (M-B) distribution, the upper bound of the velocity arises
naturally from the potential.Comment: 21 LaTex pages, 27 figure
New Velocity Distribution in the Context of the Eddington Theory
Exotic dark matter together with the vacuum energy (associated with the
cosmological constant) seem to dominate the Universe. Thus its direct detection
is central to particle physics and cosmology. Supersymmetry provides a natural
dark matter candidate, the lightest supersymmetric particle (LSP). One
essential ingredient in obtaining the direct detection rates is the density and
velocity distribution of the LSP. The detection rate is proportional to this
density in our vicinity. Furthermore, since this rate is expected to be very
low, one should explore the two characteristic signatures of the process,
namely the modulation effect, i.e. the dependence of the event rate on the
Earth's motion and the correlation of the directional rate with the motion of
the sun. Both of these crucially depend on the LSP velocity distribution. In
the present paper we study simultaneously density profiles and velocity
distributions based on the Eddington theory.Comment: 40 LaTex pages, 19 figures and one table. The previous version was
expanded to include new numerical solutions to Poisson's equation. Sheduled
to appear in vol. 588, ApJ, May 1, 300
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