18 research outputs found
Radiation spectra of laser-driven quantum relativistic electrons
A procedure to calculate the radiation spectrum emitted by an arbitrarily
prepared Dirac wave packet is developed. It is based on the Dirac charge
current and classical electrodynamic theory. Apart from giving absolute
intensity values, it is exact in terms of relativistic retardation effects and
angular dependence. We employ a laser driven free electron to demonstrate the
advantages of our method as compared to traditional ones that merely rely on
the Fourier transform of the dipole operator's expectation value. Classical
reference calculations confirm the results obtained for the low-frequency part
of the spectrum, especially in terms of the observed red-shifts, which clearly
deviate from non-relativistic calculations. In the high-frequency part of the
spectrum, we note appreciable deviations to the purely classical calculations
which may be linked to quantum averaging effects.Comment: 30 pages, 7 figure
Pair production in laser fields oscillating in space and time
The production of electron-positron pairs from vacuum by counterpropagating
laser beams of linear polarization is calculated. In contrast to the usual
approximate approach, the spatial dependence and magnetic component of the
laser field are taken into account. We show that the latter strongly affects
the creation process at high laser frequency: the production probability is
reduced, the kinematics is fundamentally modified, the resonant
Rabi-oscillation pattern is distorted and the resonance positions are shifted,
multiplied and split.Comment: 5 pages, 5 figure
Quantum signatures in laser-driven relativistic multiple-scattering
The dynamics of an electronic Dirac wave packet evolving under the influence
of an ultra-intense laser pulse and an ensemble of highly charged ions is
investigated numerically. Special emphasis is placed on the evolution of
quantum signatures from single to multiple scattering events. We quantify the
occurrence of quantum relativistic interference fringes in various situations
and stress their significance in multiple-particle systems, even in the
relativistic range of laser-matter interaction.Comment: 4 pages, 2 figures, LaTeX, revtex
Laser-induced nonresonant nuclear excitation in muonic atoms
Coherent nuclear excitation in strongly laser-driven muonic atoms is
calculated. The nuclear transition is caused by the time-dependent Coulomb
field of the oscillating charge density of the bound muon. A closed-form
analytical expression for electric multipole transitions is derived and applied
to various isotopes; the excitation probabilities are in general very small. We
compare the process with other nuclear excitation mechanisms through coupling
with atomic shells and discuss the prospects to observe it in experiment.Comment: 7 pages, 5 figure
Entwicklung, Erprobung und Optimierung eines umweltvertraeglichen Faerbereiverfahrens zur Reduktion der Abwasserbelastung Abschlussbericht
SIGLEAvailable from TIB Hannover: F01B1058 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDeutsche Bundesstiftung Umwelt, Osnabrueck (Germany)DEGerman