595 research outputs found
Some properties of the resonant state in quantum mechanics and its computation
The resonant state of the open quantum system is studied from the viewpoint
of the outgoing momentum flux. We show that the number of particles is
conserved for a resonant state, if we use an expanding volume of integration in
order to take account of the outgoing momentum flux; the number of particles
would decay exponentially in a fixed volume of integration. Moreover, we
introduce new numerical methods of treating the resonant state with the use of
the effective potential. We first give a numerical method of finding a
resonance pole in the complex energy plane. The method seeks an energy
eigenvalue iteratively. We found that our method leads to a super-convergence,
the convergence exponential with respect to the iteration step. The present
method is completely independent of commonly used complex scaling. We also give
a numerical trick for computing the time evolution of the resonant state in a
limited spatial area. Since the wave function of the resonant state is
diverging away from the scattering potential, it has been previously difficult
to follow its time evolution numerically in a finite area.Comment: 20 pages, 12 figures embedde
A note on a local ergodic theorem for an infinite tower of coverings
This is a note on a local ergodic theorem for a symmetric exclusion process
defined on an infinite tower of coverings, which is associated with a finitely
generated residually finite amenable group.Comment: Final version to appear in Springer Proceedings in Mathematics and
Statistic
Multiwavelength observation from radio through very-high-energy Gamma-ray of OJ 287 during the 12-year cycle flare in 2007
We performed simultaneous multiwavelength observations of OJ 287 with the
Nobeyama Millimeter Array for radio, the KANATA telescope and the KVA telescope
for optical, the Suzaku satellite for X-ray and the MAGIC telescope for very
high energy (VHE) gamma-ray in 2007. The observations were conducted for a
quiescent state in April and in a flaring state in November-December. We
clearly observed increase of fluxes from radio to X-ray bands during the
flaring state while MAGIC could not detect significant VHE gamma-ray emission
from the source. We could derive an upper limit (95% confidence level) of 1.7%
of the Crab Nebula flux above 150 GeV from about 41.2 hours of the MAGIC
observation. A simple SSC model suggests that the observed flaring activity
could be caused by evolutions in the distribution of the electron population
rather than changes of the magnetic field strength or Doppler beaming factor in
the jet.Comment: Contribution to the 31st ICRC, Lodz, Poland, July 200
Infrared/optical - X-ray simultaneous observations of X-ray flares in GRB 071112C and GRB 080506
We investigate the origin of short X-ray flares which are occasionally
observed in early stages of afterglows of gamma-ray bursts (GRBs). We observed
two events, GRB 071112C and GRB 080506, before the start of X-ray flares in the
optical and near-infrared (NIR) bands with the 1.5-m Kanata telescope. In
conjunction with published X-ray and optical data, we analyzed densely sampled
light curves of the early afterglows and spectral energy distributions (SEDs)
in the NIR-X-ray ranges. We found that the SEDs had a break between the optical
and X-ray bands in the normal decay phases of both GRBs regardless of the model
for the correction of the interstellar extinction in host galaxies of GRBs. In
the X-ray flares, X-ray flux increased by 3 and 15 times in the case of GRB
071112C and 080506, respectively, and the X-ray spectra became harder than
those in the normal decay phases. No significant variation in the optical-NIR
range was detected together with the X-ray flares. These results suggest that
the X-ray flares were associated with either late internal shocks or external
shocks from two-component jets.Comment: 10 pages, 5 figures, accepted to Astronomy and Astrophysic
Hydrodynamic limit for weakly asymmetric simple exclusion processes in crystal lattices
We investigate the hydrodynamic limit for weakly asymmetric simple exclusion
processes in crystal lattices. We construct a suitable scaling limit by using a
discrete harmonic map. As we shall observe, the quasi-linear parabolic equation
in the limit is defined on a flat torus and depends on both the local structure
of the crystal lattice and the discrete harmonic map. We formulate the local
ergodic theorem on the crystal lattice by introducing the notion of local
function bundle, which is a family of local functions on the configuration
space. The ideas and methods are taken from the discrete geometric analysis to
these problems. Results we obtain are extensions of ones by Kipnis, Olla and
Varadhan to crystal lattices.Comment: 41 pages, 7 figure
A peculiar multi-wavelength flare in the Blazar 3C 454.3
The blazar 3C454.3 exhibited a strong flare seen in gamma-rays, X-rays, and
optical/NIR bands during 3--12 December 2009. Emission in the V and J bands
rose more gradually than did the gamma-rays and soft X-rays, though all peaked
at nearly the same time. Optical polarization measurements showed dramatic
changes during the flare, with a strong anti-correlation between optical flux
and degree of polarization (which rose from ~ 3% to ~ 20%) during the declining
phase of the flare. The flare was accompanied by large rapid swings in
polarization angle of ~ 170 degree. This combination of behaviors appear to be
unique. We have cm-band radio data during the same period but they show no
correlation with variations at higher frequencies. Such peculiar behavior may
be explained using jet models incorporating fully relativistic effects with a
dominant source region moving along a helical path or by a shock-in-jet model
incorporating three-dimensional radiation transfer if there is a dominant
helical magnetic field. We find that spectral energy distributions at different
times during the flare can be fit using modified one-zone models where only the
magnetic field strength and particle break frequencies and normalizations need
change. An optical spectrum taken at nearly the same time provides an estimate
for the central black hole mass of ~ 2.3 * 10^9 M_sun. We also consider two
weaker flares seen during the d span over which multi-band data are
available. In one of them, the V and J bands appear to lead the -ray
and X-ray bands by a few days; in the other, all variations are simultaneous.Comment: 11 pages, 4 figures, 2 tables; MNRAS in pres
Nano-displacement measurements using spatially multimode squeezed light
We demonstrate the possibility of surpassing the quantum noise limit for
simultaneous multi-axis spatial displacement measurements that have zero mean
values. The requisite resources for these measurements are squeezed light beams
with exotic transverse mode profiles. We show that, in principle, lossless
combination of these modes can be achieved using the non-degenerate Gouy phase
shift of optical resonators. When the combined squeezed beams are measured with
quadrant detectors, we experimentally demonstrate a simultaneous reduction in
the transverse x- and y- displacement fluctuations of 2.2 dB and 3.1 dB below
the quantum noise limit.Comment: 21 pages, 9 figures, submitted to "Special Issue on Fluctuations &
Noise in Photonics & Quantum Optics" of J. Opt.
Early phase observations of extremely luminous Type Ia Supernova 2009dc
We present early phase observations in optical and near-infrared wavelengths
for the extremely luminous Type Ia supernova (SN Ia) 2009dc. The decline rate
of the light curve is , which is one of the
slowest among SNe Ia. The peak -band absolute magnitude is mag even if the host extinction is mag. It reaches
mag for the host extinction of mag as
inferred from the observed Na {\sc i} D line absorption in the host. Our
-band photometry shows that the SN is one of the most luminous SNe Ia
also in near-infrared wavelengths. These results indicate that SN 2009dc
belongs to the most luminous class of SNe Ia, like SN 2003fg and SN 2006gz. We
estimate the ejected Ni mass of \Msun for no host
extinction case (or 1.6 0.4 M for the host extinction of
mag). The C {\sc ii} 6580 absorption line keeps visible
until a week after maximum, which diminished in SN 2006gz before its maximum
brightness. The line velocity of Si {\sc ii} 6355 is about 8000 km
s around the maximum, being considerably slower than that of SN 2006gz,
while comparable to that of SN 2003fg. The velocity of the C {\sc ii} line is
almost comparable to that of the Si {\sc ii}. The presence of the carbon line
suggests that thick unburned C+O layers remain after the explosion. SN 2009dc
is a plausible candidate of the super-Chandrasekhar mass SNe Ia
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