430 research outputs found
Radial coherent and intelligent states of paraxial wave equation
Ladder operators for the radial index of the paraxial optical modes in the
cylindrical coordinates are calculated. The operators obey the su(1,1) algebra
commutation relations. Based on this Lie algebra, we found that coherent modes
constructed as eigenstates of the destruction operator or resulting from the
action of the displacement operator on the fundamental mode are different. Some
properties of these two kinds of radial coherent modes are studied in detail.Comment: 3 pages, 3 figure
THE EFFECT OF FOUR WEEKS HIIT TRAINING WITH THE USE OF L-CARNITINE ON FAT PERCENTAGE OF TRAINED OVERWEIGHT WOMEN
The change in phenotype of adipose tissue as a result of practice is a new theory that has recently been proposed and its cell-molecular mechanism is under investigation. The aim of this study was to investigate the effect of high-intensity interval associated with consumption of L-Carnitine on body composition factors in the selective Orexin hormone. The population was trained overweight women, 25 to 35, and out of which, 40 persons voluntarily participated in the study and were divided randomly into 4 groups of 10 people of L-Carnitine, placebo, HIIT and placebo, HIIT L-carnitine. For the sports background and non-suffering of disease, a questionnaire was used. After explaining on implementing the protocol, measuring body composition and blood samples were conducted. Next, the subjects were participated in an intense training programme (with a maximum power) during 12 sessions. Each of the exercise includes a 10-minute warm-up and then a repeated 10 times for 30 seconds and, then, cool down was performed in 5 to 10 minutes. Forty-eight hours after the last training session, the necessary measurement of body composition and blood samples were conducted and data were analyzed using SPSS software and statistical methods. Four weeks of taking L-carnitine, HIIT training with placebo and with L-Carnitine has a significant effect on the percentage of body fat in overweight trained women. Four weeks of HIIT training with L-Carnitine had a significant effect on the percentage of body fat. Article visualizations
Generation of a spin-polarized electron beam by multipoles magnetic fields
The propagation of an electron beam in the presence of transverse magnetic
fields possessing integer topological charges is presented. The spin--magnetic
interaction introduces a nonuniform spin precession of the electrons that gains
a space-variant geometrical phase in the transverse plane proportional to the
field's topological charge, whose handedness depends on the input electron's
spin state. A combination of our proposed device with an electron orbital
angular momentum sorter can be utilized as a spin-filter of electron beams in a
mid-energy range. We examine these two different configurations of a partial
spin-filter generator numerically. The results of these analysis could prove
useful in the design of improved electron microscope.Comment: 7 pages, 7 figure
Trajectory of a massive localised wave function in a curved spacetime geometry
Propagation of a localised wave function of a massive scalar field is
investigated in its rest frame. The complete orthogonal Hermite-Gauss basis is
presented, and the Gouy phase and Rayleigh scale notions are adapted. The
leading and sub-leading gravitational corrections to a localised quantum wave
function propagating in a general curved spacetime geometry are calculated
within the Fermi coordinates around the time-like geodesic of its rest frame,
and cross-talk coefficients among the modes are derived. It is observed that
spherically symmetric modes propagate along the geodesic. However,
non-spherical modes are found to experience a mode-dependent residual quantum
force at the sub-leading order. It is shown that the residual force does not
generate an escape velocity for in-falling wave functions but leads to a
mode-dependent deflection angle for the scattered ones.Comment: 17 pages, 4 figures, matches the published versio
Time-division multiplexing of the orbital angular momentum of light
We present an optical setup for generating a sequence of light pulses in
which the orbital angular momentum (OAM) degree of freedom is correlated with
the temporal one. The setup is based on a single -plate within a ring
optical resonator. By this approach, we demonstrate the generation of a train
of pulses carrying increasing values of OAM, or, alternatively, of a controlled
temporal sequence of pulses having prescribed OAM superposition states.
Finally, we exhibit an "OAM-to-time conversion" apparatus dividing different
input OAM states into different time-bins. The latter application provides a
simple approach to digital spiral spectroscopy of pulsed light.Comment: 3 pages and 2 figure
Integrated multi vector vortex beam generator
A novel method to generate and manipulate vector vortex beams in an
integrated, ring resonator based geometry is proposed. We show numerically that
a ring resonator, with an appropriate grating, addressed by a vertically
displaced access waveguide emits a complex optical field. The emitted beam
possesses a specific polarization topology, and consequently a transverse
intensity profile and orbital angular momentum. We propose a combination of
several concentric ring resonators, addressed with different bus guides, to
generate arbitrary orbital angular momentum qudit states, which could
potentially be used for classical and quantum communications. Finally, we
demonstrate numerically that this device works as an orbital angular momentum
sorter with an average cross-talk of -10 dB between different orbital angular
momentum channels.Comment: 8 pages, 7 figure
Influence of generalized focusing of few-cycle Gaussian pulses in attosecond pulse generation
In contrast to the case of quasi-monochromatic waves, a focused optical pulse
in the few-cycle limit may exhibit two independent curved wavefronts,
associated with phase and group retardations, respectively. Focusing optical
elements will generally affect these two wavefronts differently, thus leading
to very different behavior of the pulse near focus. As limiting cases, we
consider an ideal diffractive lens introducing only phase retardations and a
perfect non-dispersive refractive lens (or a curved mirror) introducing equal
phase and group retardations. We study the resulting diffraction effects on the
pulse, finding both strong deformations of the pulse shape and shifts in the
spectrum. We then show how important these effects can be in highly nonlinear
optics, by studying their role in attosecond pulse generation. In particular,
the focusing effects are found to affect substantially the generation of
isolated attosecond pulses in gases from few-cycle fundamental optical fields.Comment: 8 pages and 6 figure
Quantum simulation of a spin polarization device in an electron microscope
A proposal for an electron-beam device that can act as an efficient
spin-polarization filter has been recently put forward [E. Karimi et al., Phys.
Rev. Lett. 108, 044801 (2012)]. It is based on combining the recently developed
diffraction technology for imposing orbital angular momentum to the beam with a
multipolar Wien filter inducing a sort of artificial non-relativistic
spin-orbit coupling. Here we reconsider the proposed device with a fully
quantum-mechanical simulation of the electron beam propagation, based on the
well established multi-slice method, supplemented with a Pauli term for taking
into account the spin degree of freedom. Using this upgraded numerical tool, we
study the feasibility and practical limitations of the proposed method for
spin-polarizing a free electron bea
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