626 research outputs found
Nuclear effects and higher twists in F3 structure function
We analyze the CCFR collaboration iron target data on the xF3 structure
function making particular emphasis on the extraction of the higher twist
contributions from data. Corrections for nuclear effects are applied in order
to extract data on the structure function of the isoscalar nucleon. Our
analysis confirms the observation made earlier, that the higher twist terms
depend strongly on the level to which QCD perturbation theory analysis is
applied. We discuss the impact of nuclear effects on the higher twist term as
well as on the QCD scale parameter Lambda_{\bar{MS}} extracted from the fit to
data.Comment: 16 pages, 2 figure
Production of squeezed states for macroscopic mechanical oscillator
The possibility of squeezed states generation for macroscopic mechanical oscillator is discussed. It is shown that one can obtain mechanical oscillator in squeezed state via coupling it to electromagnetic oscillator (Fabry-Perot resonator) and pumping this Fabry-Perot resonator with a field in squeezed state. The degradation of squeezing due to mechanical and optical losses is also analyzed
Room temperature GW bar detector with opto-mechanical readout
We present the full implementation of a room-temperature gravitational wave
bar detector equipped with an opto-mechanical readout. The mechanical
vibrations are read by a Fabry--Perot interferometer whose length changes are
compared with a stable reference optical cavity by means of a resonant laser.
The detector performance is completely characterized in terms of spectral
sensitivity and statistical properties of the fluctuations in the system output
signal. The new kind of readout technique allows for wide-band detection
sensitivity and we can accurately test the model of the coupled oscillators for
thermal noise. Our results are very promising in view of cryogenic operation
and represent an important step towards significant improvements in the
performance of massive gravitational wave detectors.Comment: 7 figures, submitted to Phys. Rev.
Semiclassical approach to the nonlocal nonlinear Schr\"{o}dinger equation with a non-Hermitian term
The nonlinear Sch\"{o}dinger equation (NLSE) with a non-Hermitian term is the
model for various phenomena in nonlinear open quantum systems. We deal with the
Cauchy problem for the nonlocal generalization of multidimensional NLSE with a
non-Hermitian term. Using the ideas of the Maslov method, we propose the method
of constructing asymptotic solutions to this equation within the framework of
semiclassically concentrated states. The semiclassical nonlinear evolution
operator and symmetry operators for the leading term of asymptotics are
derived. Our approach is based on the solutions of the auxiliary dynamical
system that effectively linearize the problem under certain algebraic
conditions. The formalism proposed is illustrated with the specific example of
the NLSE with a non-Hermitian term that is the model of an atom laser. The
analytical asymptotic solution to the Cauchy problem is obtained explicitly for
this example.Comment: 29 pages, 1 figur
Flying mirror model for interaction of a super-intense laser pulse with a thin plasma layer: Transparency and shaping of linearly polarized laser pulses
A self-consistent one-dimensional (1D) flying mirror model is developed for description of an interaction of an ultra-intense laser pulse with a thin plasma layer (foil). In this model, electrons of the foil can have large longitudinal displacements and relativistic longitudinal momenta. An approximate analytical solution for a transmitted field is derived. Transmittance of the foil shows not only a nonlinear dependence on the amplitude of the incident laser pulse, but also time dependence and shape dependence in the high-transparency regime. The results are compared with particle-in-cell (PIC) simulations and a good agreement is ascertained. Shaping of incident laser pulses using the flying mirror model is also considered. It can be used either for removing a prepulse or for reducing the length of a short laser pulse. The parameters of the system for effective shaping are specified. Predictions of the flying mirror model for shaping are compared with the 1D PIC simulations, showing good agreement.open
- âŠ