Search results for "shift"
showing 10 items of 1226 documents
Low-temperature X-ray detectors for precise Lamb shift measurements on hydrogen-like heavy ions
2000
The precise determination of the Lamb shift in heavy hydrogen-like ions provides a sensitive test of quantum electrodynamics in very strong Coulomb"elds, not accessible otherwise. For the investigation of the Lyman-a transitions in 208Pb81‘ or 238U91‘ with su$cient accuracy a high resolving calorimetric detector for hard X-rays (E)100 keV) is presently developed. The detector modules consist of arrays of silicon thermistors and of X-ray absorbers made of high Z material to optimize the absorption e$ciency. The detectors are housed in a specially designed 3He/4He dilution refrigerator with a side arm which "ts to the geometry of the internal target of the storage ring ESR at GSI Darmstadt. T…
Role of in-medium hadrons in photon–nucleus reactions: shadowing and dilepton spectrum
2003
We study the effect of in-medium hadronic properties in photon nucleus interactions in the context of shadowing as well as the dilepton spectrum for incident photon energies in the range 1.1- 3 GeV. A reasonable agreement with the experimental data for shadowing is obtained in a scenario of downward spectral shift of the hadrons. We show that distinguishable features for in-medium changes of the hadronic properties can be observed experimentally through the dilepton spectrum by judicious choice of target nuclei and incident energy of photons.
In-beam spectroscopic studies of shape coexistence and collectivity in the neutron-deficientZ≈ 82 nuclei
2016
In the present paper we focus on studies of shape coexistence in even-mass nuclei in the neutron-deficient Pb region. They are based on experiments carried out using tagging techniques in the Accelerator Laboratory of the University of Jyväskylä, Finland. Excited states in many of these nuclei can only be accessed via fusion-evaporation reactions employing high-intensity stable-ion beams. The key features in these experiments are high selectivity, clean spectra and instrumentation that enables high count rates. We review three spectroscopic highlights in this region. peerReviewed
A Statistical Analysis of the Nuclear Structure Uncertainties in $$\mu $$D
2020
The charge radius of the deuteron (D), was recently determined to three times the precision compared with previous measurements using the measured Lamb shift in muonic deuterium (\(\mu \)D). However, the \(\mu \)D value is 5.6 \(\sigma \) smaller than the world averaged CODATA-2014 value (Pohl R et al. (2016) Science 353:669 [1]). To shed light on this discrepancy we analyze the uncertainties of the nuclear structure calculations of the Lamb shift in \(\mu \)D and conclude that nuclear theory uncertainty is not likely to be the source of the discrepancy.
Mission: Impossible (Escape from the Lyman Limit)
2003
We investigate the intrinsic opacity of high-redshift galaxies to outgoing ionising photons using high-quality photometry of a sample of 27 spectroscopically-identified galaxies of redshift 1.9<z<3.5 in the Hubble Deep Field. Our measurement is based on maximum-likelihood fitting of model galaxy spectral energy distributions-including the effects of intrinsic Lyman-limit absorption and random realizations of intervening Lyman-series and Lyman-limit absorption-to photometry of galaxies from space- and ground-based broad-band images. Our method provides several important advantages over the methods used by previous groups, including most importantly that two-dimensional sky subtraction of fai…
A universal all-fiber Omnipolarizer
2014
We report the experimental observation of self-polarization of light in optical fibers through a counter-propagating four-wave mixing between an incident signal and its backward replica. An efficient self-polarization of a 40-Gbit/s signal is demonstrated.
Evaluation of all-optical demultiplexing in millimeter-wave subcarrier-system for wireless communication
2006
In this paper, a scheme for multiplexing millimeter-wave carriers on a single optical carrier and using an all-optical millimeter-wave demultiplexer is presented. The optical demultiplexing of radio-over-fiber signals is based on dual sideband modulation with suppressed optical carrier combined with the filtering properties of dual over-written fiber Bragg gratings. The performance of the system is investigated using a single optical carrier and independent data modulated millimeter-wave signals at 20 and 40 GHz. The signals are transmitted over optical fiber, demultiplexed and wirelessly distributed to a mobile unit. It is found that performance of the demultiplexing using fiber Bragg grat…
Experimental control over soliton interaction in optical fiber by pre-shaped input field
2011
Interactions between femtosecond solitons in a nonlinear photonic-crystal fiber are of fundamental interest. But many practical applications would abound if solitons could be arbitrarily superposed into multiples in the fiber. Here, we numerically and experimentally demonstrate a first step towards this aim, the creation of a soliton pair with arbitrary relative phase, delay, and frequency throughout almost the entire output parameter space with the aid of a pre-shaped fiber input field.
Stable coupled conjugate solitary waves in optical fibers.
1998
Four-wave mixing of an intense continuous-wave pump beam with an ultrashort soliton signal in an optical fiber is theoretically analyzed. A novel class of stable two-color coupled solitary waves is found. These vector parametric solitons represent the optimal frequency conversion of an ultrashort pulse. © 1998 Optical Society of America.
Analytical design of dispersion-managed fiber system with map strength 1.65
2003
Abstract We present an easy analytical method for designing dispersion-managed fiber systems with map strength of 1.65, where the transmission lines have minimal pulse–pulse interactions.