1,997 research outputs found
Three-dimensional numerical simulation of 1GeV/Nucleon U92+ impact against atomic hydrogen
The impact of 1GeV/Nucleon U92+ projectiles against atomic hydrogen is
studied by direct numerical resolution of the time-dependent wave equation for
the atomic electron on a three-dimensional Cartesian lattice. We employ the
fully relativistic expressions to describe the electromagnetic fields created
by the incident ion. The wave equation for the atom interacting with the
projectile is carefully derived from the time-dependent Dirac equation in order
to retain all the relevant terms.Comment: 12 pages and 7 figures included in the tex
Excitation of weakly bound Rydberg electrons by half-cycle pulses
The interaction of a weakly bound Rydberg electron with an electromagnetic
half-cycle pulse (HCP) is described with the help of a multidimensional
semiclassical treatment. This approach relates the quantum evolution of the
electron to its underlying classical dynamics. The method is nonperturbative
and is valid for arbitrary spatial and temporal shapes of the applied HCP. On
the basis of this approach angle- and energy-resolved spectra resulting from
the ionization of Rydberg atoms by HCPs are analyzed. The different types of
spectra obtainable in the sudden-impact approximation are characterized in
terms of the appearing semiclassical scattering phenomena. Typical
modifications of the spectra originating from finite pulse effects are
discussed.Comment: Submitted to Phys. Rev.
Effective low-energy theory for correlated carbon nanotubes
The low-energy theory for single-wall carbon nanotubes including Coulomb
interactions is derived and analyzed. It describes two fermion chains without
interchain hopping but coupled in a specific way by the interaction. The
strong-coupling properties are studied by bosonization, and consequences for
experiments on single armchair nanotubes are discussed.Comment: 5 pages REVTeX, includes one figur
Diagnostic criterion for crystallized beams
Small ion crystals in a Paul trap are stable even in the absence of laser
cooling. Based on this theoretically and experimentally well-established fact
we propose the following diagnostic criterion for establishing the presence of
a crystallized beam: Absence of heating following the shut-down of all cooling
devices. The validity of the criterion is checked with the help of detailed
numerical simulations.Comment: REVTeX, 11 pages, 4 figures; submitted to PR
Friedel oscillations for interacting fermions in one dimension
We study Friedel oscillations in one-dimensional electron liquid for
arbitrary electron-electron interaction and arbitrary impurity strength. For
Luttinger liquid leads, the Friedel oscillations decay as x^-g far away from
the impurity, where g is the interaction constant. For a weak scatterer, a
slower decay is found at intermediate distances from the impurity, with a
crossover to the asymptotic x^-g law.Comment: 4 pages REVTeX, includes two figure
Quantum phase retrieval of a Rydberg wave packet using a half-cycle pulse
A terahertz half-cycle pulse was used to retrieve information stored as
quantum phase in an -state Rydberg atom data register. The register was
prepared as a wave packet with one state phase-reversed from the others (the
"marked bit"). A half-cycle pulse then drove a significant portion of the
electron probability into the flipped state via multimode interference.Comment: accepted by PR
On the absence of bound-state stabilization through short ultra-intense fields
We address the question of whether atomic bound states begin to stabilize in
the short ultra-intense field limit. We provide a general theory of ionization
probability and investigate its gauge invariance. For a wide range of
potentials we find an upper and lower bound by non-perturbative methods, which
clearly exclude the possibility that the ultra intense field might have a
stabilizing effect on the atom. For short pulses we find almost complete
ionization as the field strength increases.Comment: 34 pages Late
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