344 research outputs found
Generation of unipolar half-cycle pulse via unusual reflection of a single-cycle pulse from an optically thin metallic or dielectric layer
We present a significantly different reflection process from an optically
thin flat metallic or dielectric layer and propose a strikingly simple method
to form approximately unipolar half-cycle optical pulses via reflection of a
single-cycle optical pulse. Unipolar pulses in reflection arise due to
specifics of effectively one-dimensional pulse propagation. Namely, we show
that in considered system the field emitted by a flat medium layer is
proportional to the velocity of oscillating medium charges instead of their
acceleration as it is usually the case. When the single-cycle pulse interacts
with linear optical medium, the oscillation velocity of medium charges can be
then forced to keep constant sign throughout the pulse duration. Our results
essentially differ from the direct mirror reflection and suggest a possibility
of unusual transformations of the few-cycle light pulses in linear optical
systems
Antecedents of Expatriate Spouse Adjustment: An Analysis of Japanese Spouses in the United States
This is one of the first studies investigating factors related to the adjustment of expatriate spouses. The study extends, both conceptually and methodologically, the limited research on spouse adjustment by testing the effects of language profciency and educational level on adjustment. Furthermore, it is the first study to survey non US respondents in their native language. In the end, we found that time since arrival, educational level, language proficiency, and willingness to communicate are directly related to spouse adjustment
Modulation instability, Akhmediev Breathers and continuous wave supercontinuum generation
Numerical simulations of the onset phase of continuous wave supercontinuum
generation from modulation instability show that the structure of the field as
it develops can be interpreted in terms of the properties of Akhmediev
Breathers. Numerical and analytical results are compared with experimental
measurements of spectral broadening in photonic crystal fiber using nanosecond
pulsesComment: 22 pages, 6 figure
Binary coalescence from case A evolution -- mergers and blue stragglers
We constructed some main-sequence mergers from case A binary evolution and
studied their characteristics via Eggleton's stellar evolution code. Both total
mass and orbital angular momentum are conservative in our binary evolutions.
Some mergers might be on the left of the ZAMS as defined by normal surface
composition on a CMD because of enhanced surface helium content. The study also
shows that central hydrogen content of the mergers is independent of mass. As a
consequence, we fit the formula of magnitude and B-V of the mergers when they
return back to thermal equilibrium with maximum error 0.29 and 0.037,
respectively. Employing the consequences above, we performed Monte Carlo
simulations to examine our models in NGC 2682 and NGC 2660. In NGC 2682, binary
mergers from our models cover the region with high luminosity, but its
importance is much less than that of AML. Our results are well-matched to the
observations of NGC2660 if there is about 0.5Mo of mass loss in the merger
process.Comment: 14 pages, 12 figures. accepted by MNRA
Vortex vs spinning string: Iordanskii force and gravitational Aharonov-Bohm effect
We discuss the transverse force acting on the spinning cosmic string, moving
in the background matter. It comes from the gravitational Aharonov-Bohm effect
and corresponds to the Iordanskii force acting on the vortex in superfluids,
when the vortex moves with respect to the normal component of the liquid.Comment: Latex file, 9 pages, no figures, references are added, version
submitted to JETP Let
Modulation control and spectral shaping of optical fiber supercontinuum generation in the picosecond regime
Numerical simulations are used to study how fiber supercontinuum generation
seeded by picosecond pulses can be actively controlled through the use of input
pulse modulation. By carrying out multiple simulations in the presence of
noise, we show how tailored supercontinuum Spectra with increased bandwidth and
improved stability can be generated using an input envelope modulation of
appropriate frequency and depth. The results are discussed in terms of the
non-linear propagation dynamics and pump depletion.Comment: Aspects of this work were presented in Paper ThJ2 at OECC/ACOFT 2008,
Sydney Australia 7-10 July (2008). Journal paper submitted for publication 30
July 200
Cherenkov radiation control via self-accelerating wave-packets
Cherenkov radiation is a ubiquitous phenomenon in nature. It describes electromagnetic radiation from a charged particle moving in a medium with a uniform velocity larger than the phase velocity of light in the same medium. Such a picture is typically adopted in the investigation of traditional Cherenkov radiation as well as its counterparts in different branches of physics, including nonlinear optics, spintronics and plasmonics. In these cases, the radiation emitted spreads along a “cone”, making it impractical for most applications. Here, we employ a self-accelerating optical pump wave-packet to demonstrate controlled shaping of one type of generalized Cherenkov radiation - dispersive waves in optical fibers. We show that, by tuning the parameters of the wave-packet, the emitted waves can be judiciously compressed and focused at desired locations, paving the way to such control in any physical system
Intrabiliary rupture of liver hydatid cyst: a case report and review of the literature
Herein, we report a 66 year old woman who was diagnosed to have intrabiliary rupture of liver hydatid cyst with demonstrative computed tomography, magnetic resonance imaging, and magnetic resonance cholangiopancreatography findings, with a review of the literature
Effective Mass of Composite Fermions and Fermionic Chern-Simons Theory in Temporal Gauge
The definitions of the effective mass of the composite fermion are discussed
for the half-filled Landau level problem. In a recent work, Shankar and Murthy
show a finite effective mass of the composite fermion by a canonical
transformation while the perturbative calculation gives the logarithmic
divergence of the effective mass at the Fermi surface. We will emphasize that
the different definition of the effective mass has the different physical
processes. The finite one could be defined for any momentum of the composite
fermion while the divergence only appears at the Fermi surface. We work with
the standard Halperin-Lee-Read model but in the temporal gauge. The advantage
of this gauge to be employed is that the finite effective mass could be
calculated in the Hartree-Fock approximation. Furthermore, it is precisely
equal to the result that Shankar and Murthy obtained which is well-fit with the
numerical calculation from the ground state energy analysis and a
semi-classical estimation. However, if we consider the random phase
approximation, one sees that the divergence of the effective mass of the
quasiparticle at the Fermi surface emerges again no matter that we work on the
temporal or Coulomb gauges. We develop an effective theory where the finite
effective mass serves as a `bare' effective mass and show that the same
divergence of the RPA effective mass. On the other hand, the correct behavior
of the response functions in the small band mass limit could be seen clearly in
the temporal gauge since there is a self-interaction among the magnetoplasmons.Comment: 27 pages,6 eps figure
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