Generation of attosecond xuv pulses in strong laser-atom interactions

The generation of radiation pulses that can be as short as 120 attoseconds is demonstrated theoretically. We have employed a two-dimensional exact solution of the Schrodinger equation that allows for arbitrary laser ellipticity. By manipulating the laser ellipticity in time, it is shown that one can control the wave-packet dynamics of the ejected atomic electron. The nonlinear interaction of the electron with the atomic core can thus be restricted to extremely short times. Photon energies up to 160 eV are generated. It is also shown that with a higher laser frequency, even shorter pulses can be produced. [S1050-2947(98)02211-2]

Anatomical variants of the emissary veins: unilateral aplasia of both the sigmoid sinus and the internal jugular vein and development of the petrosquamosal sinus. A rare case report

We report a case of hypoplasia of the right transverse sinus and aplasia of the ipsilateral sigmoid sinus and the internal jugular vein. In addition, development of the petrosquamosal sinus and the presence of a large middle meningeal sinus and sinus communicans were observed. A 53-year-old Caucasian woman was referred for magnetic resonance imaging (MRI) investigation due to chronic headache. On the MRI scan a solitary meningioma was observed. Finally MR 2D venography revealed this extremely rare variant. (Folia Morphol 2011; 70, 4: 305–308

Semiclassical description of multiphoton processes

We analyze strong field atomic dynamics semiclassically, based on a full time-dependent description with the Hermann-Kluk propagator. From the properties of the exact classical trajectories, in particular the accumulation of action in time, the prominent features of above threshold ionization (ATI) and higher harmonic generation (HHG) are proven to be interference phenomena. They are reproduced quantitatively in the semiclassical approximation. Moreover, the behavior of the action of the classical trajectories supports the so called strong field approximation which has been devised and postulated for strong field dynamics.Comment: 10 pages, 11 figure

Nonsequential double ionization of helium

Published versio

Time-dependent natural orbitals and occupation numbers

We report equations of motion for the occupation numbers of natural spin orbitals and show that adiabatic extensions of common functionals employed in ground-state reduced-density-matrix-functional theory have the shortcoming of leading always to occupation numbers which are independent of time. We illustrate the exact time-dependence of the natural spin orbitals and occupation numbers for the case of electron-ion scattering and for atoms in strong laser fields. In the latter case, we observe strong variations of the occupation numbers in time.Comment: 5 pages, 5 figure

The Myth of the Angry Atheist

Atheists are often portrayed in the media and elsewhere as angry individuals. Although atheists disagree with the pillar of many religions, namely the existence of a God, it may not necessarily be the case that they are angry individuals. The prevalence and accuracy of angry-atheist perceptions were examined in 7 studies with 1,677 participants from multiple institutions and locations in the United States. Studies 1–3 revealed that people believe atheists are angrier than believers, people in general, and other minority groups, both explicitly and implicitly. Studies 4–7 then examined the accuracy of these beliefs. Belief in God, state anger, and trait anger were assessed in multiple ways and contexts. None of these studies supported the idea that atheists are particularly angry individuals. Rather, these results support the idea that people believe atheists are angry individuals, but they do not appear to be angrier than other individuals in reality

A two-dimensional, two-electron model atom in a laser pulse: exact treatment, single active electron-analysis, time-dependent density functional theory, classical calculations, and non-sequential ionization

Owing to its numerical simplicity, a two-dimensional two-electron model atom, with each electron moving in one direction, is an ideal system to study non-perturbatively a fully correlated atom exposed to a laser field. Frequently made assumptions, such as the ``single active electron''- approach and calculational approximations, e.g. time dependent density functional theory or (semi-) classical techniques, can be tested. In this paper we examine the multiphoton short pulse-regime. We observe ``non-sequential'' ionization, i.e.\ double ionization at lower field strengths as expected from a sequential, single active electron-point of view. Since we find non-sequential ionization also in purely classical simulations, we are able to clarify the mechanism behind this effect in terms of single particle trajectories. PACS Number(s): 32.80.RmComment: 10 pages, 16 figures (gzipped postscript), see also http://www.physik.tu-darmstadt.de/tqe

Mesoscopic Phase Separation in Anisotropic Superconductors

General properties of anisotropic superconductors with mesoscopic phase separation are analysed. The main conclusions are as follows: Mesoscopic phase separation can be thermodynamically stable only in the presence of repulsive Coulomb interactions. Phase separation enables the appearance of superconductivity in a heterophase sample even if it were impossible in pure-phase matter. Phase separation is crucial for the occurrence of superconductivity in bad conductors. Critical temperature for a mixture of pairing symmetries is higher than the critical temperature related to any pure gap-wave symmetry of this mixture. In bad conductors, the critical temperature as a function of the superconductivity fraction has a bell shape. Phase separation makes the single-particle energy dispersion softer. For planar structures phase separation suppresses d-wave superconductivity and enhances s-wave superconductivity. These features are in agreement with experiments for cuprates.Comment: Revtex file, 25 pages, 2 figure