252 research outputs found
Introductory Chapter: Chromatic Dispersion Monitoring in Synchronization Channel of Quantum Key Distribution Systems with Carrier Modulation Coding
Universal Microwave Photonics Approach to Frequency-Coded Quantum Key Distribution
Design principles of universal microwave photonics system (MPS) for quantum key distribution (QKD) with frequency coding are concerned. Its main modulation concept lies in single photon generation on sidebands of optical carrier and determination of photons ground state through its registration and the amplitude value of its carrier frequency as reference channel. So, it is necessary to solve problems of signal-to-carrier ratio of single photon detector (SPD) and aspects of photon number splitting (PNS) attack, nonlinear phase modulation (NPM) between carrier and sidebands in fiber, and finally, spectral selection of carrier in receiver. The technologies, based on the modulation conversion of an optical carrier, are widely used in microwave photonics. Due to the natural symmetry of modulated signals and the highest achievable ratio of the modulation conversions, amplitude-phase modulation with complete or partial suppression of the optical carrier has found a particularly wide application in MPS. The characteristics of advanced MPS for QKD with frequency coding and carrier suppression based on tandem amplitude modulation and phase commutation are presented. New systems can have classical symmetric or non-classical asymmetric structure for QKD based only on spectral selection of carrier and subcarriers without re-modulation
Poly-harmonic Analysis of Raman and Mandelstam-Brillouin Scatterings and Bragg Reflection Spectra
Radio Photonic Systems for Measurement of Instantaneous Radio Frequency with Amplitude-phase Modulation of Optical Carrier, Journal of Telecommunications and Information Technology, 2016, nr 2
In this article questions related to the development instantaneous radio frequency measurement system based on application in them original ways of the amplitude-phase modulation transformation of single-frequency optical carrier by a radio signal in symmetric two-frequency and measuring “frequency-amplitude” transformation in fiber Bragg grating with special profile are considered. Such systems have broad prospects for use in telecommunications, military systems and for environmental monitoring
Symmetries of Differential Equations via Cartan's Method of Equivalence
We formulate a method of computing invariant 1-forms and structure equations
of symmetry pseudo-groups of differential equations based on Cartan's method of
equivalence and the moving coframe method introduced by Fels and Olver. Our
apparoach does not require a preliminary computation of infinitesimal defining
systems, their analysis and integration, and uses differentiation and linear
algebra operations only. Examples of its applications are given.Comment: 15 pages, LaTeX 2.0
Demonstration of the temporal matter-wave Talbot effect for trapped matter waves
We demonstrate the temporal Talbot effect for trapped matter waves using
ultracold atoms in an optical lattice. We investigate the phase evolution of an
array of essentially non-interacting matter waves and observe matter-wave
collapse and revival in the form of a Talbot interference pattern. By using
long expansion times, we image momentum space with sub-recoil resolution,
allowing us to observe fractional Talbot fringes up to 10th order.Comment: 17 pages, 7 figure
Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at GeV
Identified mid-rapidity particle spectra of , , and
from 200 GeV p+p and d+Au collisions are reported. A
time-of-flight detector based on multi-gap resistive plate chamber technology
is used for particle identification. The particle-species dependence of the
Cronin effect is observed to be significantly smaller than that at lower
energies. The ratio of the nuclear modification factor () between
protons and charged hadrons () in the transverse momentum
range GeV/c is measured to be
(stat)(syst) in minimum-bias collisions and shows little
centrality dependence. The yield ratio of in minimum-bias d+Au
collisions is found to be a factor of 2 lower than that in Au+Au collisions,
indicating that the Cronin effect alone is not enough to account for the
relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from
transverse momentum 1.8 GeV/c to 3. GeV/
Azimuthal anisotropy at RHIC: the first and fourth harmonics
We report the first observations of the first harmonic (directed flow, v_1),
and the fourth harmonic (v_4), in the azimuthal distribution of particles with
respect to the reaction plane in Au+Au collisions at the Relativistic Heavy Ion
Collider (RHIC). Both measurements were done taking advantage of the large
elliptic flow (v_2) generated at RHIC. From the correlation of v_2 with v_1 it
is determined that v_2 is positive, or {\it in-plane}. The integrated v_4 is
about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8)
harmonics upper limits on the magnitudes are reported.Comment: 6 pages with 3 figures, as accepted for Phys. Rev. Letters The data
tables are at
http://www.star.bnl.gov/central/publications/pubDetail.php?id=3
Mid-rapidity anti-proton to proton ratio from Au+Au collisions at GeV
We report results on the ratio of mid-rapidity anti-proton to proton yields
in Au+Au collisions at \rts = 130 GeV per nucleon pair as measured by the
STAR experiment at RHIC. Within the rapidity and transverse momentum range of
and 0.4 1.0 GeV/, the ratio is essentially independent of
either transverse momentum or rapidity, with an average of for minimum bias collisions. Within errors, no
strong centrality dependence is observed. The results indicate that at this
RHIC energy, although the -\pb pair production becomes important at
mid-rapidity, a significant excess of baryons over anti-baryons is still
present.Comment: 5 pages, 3 figures, accepted by Phys. Rev. Let
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