1,476 research outputs found
Accuracy of Trace Formulas
Using quantum maps we study the accuracy of semiclassical trace formulas. The
role of chaos in improving the semiclassical accuracy, in some systems, is
demonstrated quantitatively. However, our study of the standard map cautions
that this may not be most general. While studying a sawtooth map we demonstrate
the rather remarkable fact that at the level of the time one trace even in the
presence of fixed points on singularities the trace formula may be exact, and
in any case has no logarithmic divergences observed for the quantum bakers map.
As a byproduct we introduce fantastic periodic curves akin to curlicues.Comment: 20 pages, uuencoded and gzipped, 1 LaTex text file and 9 PS files for
figure
Cosmological Effects of Powerful AGN Outbursts in Galaxy Clusters: Insights from an XMM-Newton Observation of MS0735+7421
We report on the results of an analysis of XMM-Newton observations of
MS0735+7421, the galaxy cluster which hosts the most energetic AGN outburst
currently known. The previous Chandra image shows twin giant X-ray cavities
(~200 kpc diameter) filled with radio emission and surrounded by a weak shock
front. XMM data are consistent with these findings. The total energy in
cavities and shock (~6 \times 10^{61} erg) is enough to quench the cooling flow
and, since most of the energy is deposited outside the cooling region (~100
kpc), to heat the gas within 1 Mpc by ~1/4 keV per particle. The cluster
exhibits an upward departure (factor ~2) from the mean L-T relation. The boost
in emissivity produced by the ICM compression in the bright shells due to the
cavity expansion may contribute to explain the high luminosity and high central
gas mass fraction that we measure. The scaled temperature and metallicity
profiles are in general agreement with those observed in relaxed clusters.
Also, the quantities we measure are consistent with the observed M-T relation.
We conclude that violent outbursts such as the one in MS0735+7421 do not cause
dramatic instantaneous departures from cluster scaling relations (other than
the L-T relation). However, if they are relatively common they may play a role
in creating the global cluster properties.Comment: 69 pages, 30 figures, accepted for publication in ApJ Main Journa
Matter-field theory of the Casimir force
A matter-field theory of the Casimir force is formulated in which the
electromagnetic field and collective modes of dielectric media are treated on
an equal footing. In our theory, the Casimir force is attributed to zero-point
energies of the combined matter-field modes. We analyze why some of the
existing theories favor the interpretation of the Casimir force as originating
from zero-point energies of the electromagnetic field and others from those of
the matter.Comment: 12pages, 1 Postscript figur
Nonequilibrium Cooper pairing in the nonadiabatic regime
We obtain a complete solution for the mean-field dynamics of the BCS paired
state with a large, but finite number of Cooper pairs in the non-adiabatic
regime. We show that the problem reduces to a classical integrable Hamiltonian
system and derive a complete set of its integrals of motion. The condensate
exhibits irregular multi-frequency oscillations ergodically exploring the part
of the phase-space allowed by the conservation laws. In the thermodynamic limit
however the system can asymptotically reach a steady state.Comment: 4 pages, no figure
Functional Approach to Quantum Decoherence and the Classical Final Limit
For a wide set of quantum systems it is demonstrated that the quantum regime
can be considered as the transient phase while the final classical statistical
regime is a permanent state. A basis where exact matrix decoherence appears for
these final states is found. The relation with the decoherence of histories
formalism is studied. A set of final intrinsically consistent histories is
found.Comment: 20 pages. Phys. Rev A in press 200
Improved Precision Measurement of the Casimir Force
We report an improved precision measurement of the Casimir force. The force
is measured between a large Al coated sphere and flat plate using an Atomic
Force Microscope. The primary experimental improvements include the use of
smoother metal coatings, reduced noise, lower systematic errors and independent
measurement of surface separations. Also the complete dielectric spectrum of
the metal is used in the theory. The average statistical precision remains at
the same 1% of the forces measured at the closest separation
Psi-Series Solution of Fractional Ginzburg-Landau Equation
One-dimensional Ginzburg-Landau equations with derivatives of noninteger
order are considered. Using psi-series with fractional powers, the solution of
the fractional Ginzburg-Landau (FGL) equation is derived. The leading-order
behaviours of solutions about an arbitrary singularity, as well as their
resonance structures, have been obtained. It was proved that fractional
equations of order with polynomial nonlinearity of order have the
noninteger power-like behavior of order near the singularity.Comment: LaTeX, 19 pages, 2 figure
On elliptic solutions of the quintic complex one-dimensional Ginzburg-Landau equation
The Conte-Musette method has been modified for the search of only elliptic
solutions to systems of differential equations. A key idea of this a priory
restriction is to simplify calculations by means of the use of a few Laurent
series solutions instead of one and the use of the residue theorem. The
application of our approach to the quintic complex one-dimensional
Ginzburg-Landau equation (CGLE5) allows to find elliptic solutions in the wave
form. We also find restrictions on coefficients, which are necessary conditions
for the existence of elliptic solutions for the CGLE5. Using the investigation
of the CGLE5 as an example, we demonstrate that to find elliptic solutions the
analysis of a system of differential equations is more preferable than the
analysis of the equivalent single differential equation.Comment: LaTeX, 21 page
Constraints for hypothetical interactions from a recent demonstration of the Casimir force and some possible improvements
The Casimir force is calculated in the configuration of a spherical lens and
a disc of finite radius covered by and thin layers which was used in
a recent experiment. The correction to the Casimir force due to finiteness of
the disc radius is shown to be negligible. Also the corrections are discussed
due to the finite conductivity, large-scale and short-scale deviations from the
perfect shape of the bounding surfaces and the temperature correction. They
were found to be essential when confronting the theoretical results with
experimental data. Both Yukawa-type and power-law hypothetical forces are
computed which may act in the configuration under consideration due to the
exchange of light and/or massless elementary particles between the atoms of the
lens and the disc. New constraints on the constants of these forces are
determined which follow from the fact that they were not observed within the
limits of experimental errors. For Yukawa-type forces the new constraints are
up to 30 times stronger than the best ones known up today. A possible
improvement of experimental parameters is proposed which gives the possibility
to strengthen constraints on Yukawa-type interactions up to times and on
power-law interactions up to several hundred times.Comment: 15 pages, 3 figures, subm. to Phys. Rev.
Radiative Efficiency and Content of Extragalactic Radio Sources: Toward a Universal Scaling Relation Between Jet Power and Radio Power
We present an analysis of the energetics and particle content of the lobes of
24 radio galaxies at the cores of cooling clusters. The radio lobes in these
systems have created visible cavities in the surrounding hot, X-ray-emitting
gas, which allow direct measurement of the mechanical jet power of radio
sources over six decades of radio luminosity, independently of the radio
properties themselves. Using these measurements, we examine the ratio between
radio power and total jet power (the radiative efficiency). We find that jet
(cavity) power increases with radio synchrotron power approximately as P_jet ~
(L_radio)^beta, where 0.35 < beta < 0.70 depending on the bandpass of
measurement and state of the source. However, the scatter about these relations
caused by variations in radiative efficiency spans more than four orders of
magnitude. After accounting for variations in synchrotron break frequency
(age), the scatter is reduced by ~ 50%, yielding the most accurate scaling
relation available between the lobe bolometric radio power and the jet (cavity)
power. We place limits on the magnetic field strengths and particle content of
the radio lobes using a variety of X-ray constraints. We find that the lobe
magnetic field strengths vary between a few to several tens of microgauss
depending on the age and dynamical state of the lobes. If the cavities are
maintained in pressure balance with their surroundings and are supported by
internal fields and particles in equipartition, the ratio of energy in
electrons to heavy particles (k) must vary widely from approximately unity to
4000, consistent with heavy (hadronic) jets.Comment: 20 pages, 11 figures. Accepted for publication in Ap
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