2,078 research outputs found
Collective modes and correlations in one-component plasmas
The static and time-dependent potential and surface charge correlations in a
plasma with a boundary are computed for different shapes of the boundary. The
case of a spheroidal or spherical one-component plasma is studied in detail
because experimental results are available for such systems. Also, since there
is some knowlegde both experimental and theoretical about the electrostatic
collective modes of these plasmas, the time-dependent correlations are computed
using a method involving these modes.Comment: 20 pages, plain TeX, submitted to Phys. Rev.
The Pegg-Barnett Formalism and Covariant Phase Observables
We compare the Pegg-Barnett (PB) formalism with the covariant phase
observable approach to the problem of quantum phase and show that PB-formalism
gives essentially the same results as the canonical (covariant) phase
observable. We also show that PB-formalism can be extended to cover all
covariant phase observables including the covariant phase observable arising
from the angle margin of the Husimi Q-function.Comment: 10 page
A dilemma in representing observables in quantum mechanics
There are self-adjoint operators which determine both spectral and
semispectral measures. These measures have very different commutativity and
covariance properties. This fact poses a serious question on the physical
meaning of such a self-adjoint operator and its associated operator measures.Comment: 10 page
Voting on Growth Control Measures: Preferences and Strategies
Citizens of many California cities and counties have sought to restrict the rate of population growth in their localities. In 1988, Citizens for Limited Growth used the initiative process to place a pair of growth control measures on the ballot in the City and County of San Diego, respectively. The City Council and Board of Supervisors responded by placing less stringent, competing measures on the same ballot. This paper analyzes voting data from this election to examine the nature of support for such measures. We find strong support for the hypotheses that whites, homeowners, liberal/environmentalists, and those exposed to high levels of traffic congestion are more likely to favor growth controls. This paper also investigates the behavior of voters when they confront competing propositions concerning the same issue on the same ballot, and finds strong evidence of strategic voting
Dynamic Phase Transitions in Cell Spreading
We monitored isotropic spreading of mouse embryonic fibroblasts on
fibronectin-coated substrates. Cell adhesion area versus time was measured via
total internal reflection fluorescence microscopy. Spreading proceeds in
well-defined phases. We found a power-law area growth with distinct exponents
a_i in three sequential phases, which we denote basal (a_1=0.4+-0.2), continous
(a_2=1.6+-0.9) and contractile (a_3=0.3+-0.2) spreading. High resolution
differential interference contrast microscopy was used to characterize local
membrane dynamics at the spreading front. Fourier power spectra of membrane
velocity reveal the sudden development of periodic membrane retractions at the
transition from continous to contractile spreading. We propose that the
classification of cell spreading into phases with distinct functional
characteristics and protein activity patterns serves as a paradigm for a
general program of a phase classification of cellular phenotype. Biological
variability is drastically reduced when only the corresponding phases are used
for comparison across species/different cell lines.Comment: 4 pages, 5 figure
Static potential in baryon
The baryon static potential is calculated in the framework of field
correlator method and is shown to match the recent lattice results. The effects
of the nonzero value of the gluon correlation length are emphasized.Comment: 7 pages, 4 figures, talk at the NPD-2002 Conference, December 2-6,
ITEP, Mosco
Decoherence in Ion Trap Quantum Computers
The {\it intrinsic} decoherence from vibrational coupling of the ions in the
Cirac-Zoller quantum computer [Phys. Rev. Lett. {\bf 74}, 4091 (1995)] is
considered. Starting from a state in which the vibrational modes are at a
temperature , and each ion is in a superposition of an excited and a ground
state, an adiabatic approximation is used to find the inclusive probability
for the ions to evolve as they would without the vibrations, and for the
vibrational modes to evolve into any final state. An analytic form is found for
at , and the decoherence time is found for all . The decoherence
is found to be quite small, even for 1000 ions.Comment: 11 pages, no figures, uses revte
Vibrating the QCD string
The large distance behaviour of the adiabatic hybrid potentials is studied in
the framework of the QCD string model. The calculated spectra are shown to be
the result of interplay between potential-type longitudinal and string-type
transverse vibrations.Comment: LaTeX2e, 9 pages, 2 Postscript figures, final version to appear in
Yad.Fi
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