1,281 research outputs found
Lindstedt Series Solutions of the Fermi-Pasta-Ulam Lattice
We apply the Lindstedt method to the one dimensional Fermi-Pasta-Ulam
lattice to find fully general solutions to the complete set of equations of
motion. The pertubative scheme employed uses as the expansion
parameter, where is the coefficient of the quartic coupling between
nearest neighbors. We compare our non-secular perturbative solutions to
numerical solutions and find striking agreement.Comment: 17 pages, 10 figures. To appear in the Journal of Mathematical
Physic
Rigorous theory of nuclear fusion rates in a plasma
Real-time thermal field theory is used to reveal the structure of plasma
corrections to nuclear reactions. Previous results are recovered in a fashion
that clarifies their nature, and new extensions are made. Brown and Yaffe have
introduced the methods of effective quantum field theory into plasma physics.
They are used here to treat the interesting limiting case of dilute but very
highly charged particles reacting in a dilute, one-component plasma. The highly
charged particles are very strongly coupled to this background plasma. The
effective field theory proves that this mean field solution plus the one-loop
term dominate; higher loop corrections are negligible even though the problem
involves strong coupling. Such analytic results for very strong coupling are
rarely available, and they can serve as benchmarks for testing computer models.Comment: 4 pages and 2 figures, presented at SCCS 2005, June 20-25, Moscow,
Russi
A model of CP Violation from Extra Dimension
We construct a realistic model of CP violation in which CP is broken in the
process of dimensional reduction and orbifold compactification from a five
dimensional theories with gauge symmetry. CP
violation is a result of the Hosotani type gauge configuration in the higher
dimension.Comment: 5 page
Bunch stabilization using rf phase modulation in the intense pulse neutron source (IPNS) rapid cycling synchrotron (RCS)
Phase modulation (PM) is used to increase the current limit in the IPNS RCS. A device referred to as a scrambler introduces a small oscillating phase between the two RCS rf cavities at approximately twice the synchrotrons frequency, f{sub s}. The modulation introduced by the scrambler generates longitudinal oscillations in the bunch at 2f{sub s}. Modulations in the bunch are also observed transversely indicating a coupling between longitudinal and transverse motion. Comparing PM with amplitude modulation (AM), coupling to the beam is roughly equivalent at 2f{sub s}
Four--Neutrino Oscillation Solutions of the Solar Neutrino Problem
We present an analysis of the neutrino oscillation solutions of the solar
neutrino problem in the framework of four-neutrino mixing where a sterile
neutrino is added to the three standard ones. We perform a fit to the full data
set corresponding to the 825-day Super-Kamiokande data sample as well as to
Chlorine, GALLEX and SAGE and Kamiokande experiments. In our analysis we use
all measured total event rates as well as all Super-Kamiokande data on the
zenith angle dependence and the recoil electron energy spectrum. We consider
both transitions via the Mikheyev-Smirnov-Wolfenstein (MSW) mechanism as well
as oscillations in vacuum (just-so) and find the allowed solutions for
different values of the additional mixing angles. This framework permits
transitions into active or sterile neutrinos controlled by the additional
parameter . We discuss the
maximum allowed values of this additional mixing parameter for the different
solutions.Comment: 28 pages Latex file using RevTeX. 8 postscript figures included
(bitmapped for compression). Detailed explanation of criterion 3 and lower
two graphs of Fig. 8. Misprints corrected in table II.A full version of the
paper can be found at http://ific.uv.es/~penya/papers/four
Can R-parity violation explain the LSND data as well?
The recent Super-Kamiokande data now admit only one type of mass hierarchy in
a framework with three active and one sterile neutrinos. We show that neutrino
masses and mixings generated by R-parity-violating couplings, with values
within their experimental upper limits, are capable of reproducing this
hierarchy, explaining all neutrino data particularly after including the LSND
results.Comment: 7 pages, Latex, 3 PS figures; in v2 a few clarifying remarks included
and two references added (to appear in Physical Review D
Aircraft sound exposure leads to song frequency decline and elevated aggression in wild chiffchaffs
The ubiquitous anthropogenic low-frequency noise impedes communication by masking animal signals. To overcome this communication barrier, animals may increase the frequency, amplitude and delivery rate of their acoustic signals, making them more easily heard. However, a direct impact of intermittent, high-level aircraft noise on birds’ behaviour living close to a runway has not been studies in detail. 2. We recorded common chiffchaffs Phylloscopus collybita songs near two airports and nearby control areas, and we measured sound levels in their territories at Manchester airport. The song recordings were made in between aircraft movements, when ambient sound levels were similar between airport and control populations. We also conducted playback experiments at the airport and a control population to test the salience of airport, and control population specific songs. 3. In contrast to the general pattern of increased song frequency in noisy areas, we show that common chiffchaffs at airports show a negative relationship between noise exposure level and song frequency. 4. Experimental data show that chiffchaffs living near airports also respond more aggressively to song playback. 5. Since the decrease in song frequency results in increased overlap with aircraft noise, these findings cannot be explained as an adaptation to improve communication. The increased levels of aggression suggests that chiffchaffs, like humans, might be affected behaviourally by extreme noise pollution. These findings should influence environmental impact assessments for airport expansions globally
Matter Effects on Neutrino Oscillations in Long Baseline Experiments
We calculate matter effects on neutrino oscillations relevant for long
baseline experiments. In particular, we compare the results obtained with
constant density along the neutrino path versus results obtained by
incorporating the actual density profiles in the Earth. We study the dependence
of the oscillation signal on both and on the angles in the
leptonic mixing matrix. We also comment on the influence of
on the oscillations. The results show quantitatively how, as a function of
these input parameters, matter effects can cause significant (25 %) changes in
the oscillation probabilities. An important conclusion is that matter effects
can be useful in amplifying certain neutrino oscillation signals and helping
one to obtain measurements of mixing parameters and the magnitude and sign of
.Comment: 26 pages, Latex, 17 postscript figures, published version, some
references adde
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