Analytical solution to the Schrodinger equation of a laser-driven correlated two-particle system

The time-dependent quantum system of two laser-driven electrons in a harmonic oscillator potential is analysed, taking into account the repulsive Coulomb interaction between both particles. The Schrodinger equation of the two-particle system is shown to be analytically soluble in case of arbitrary laser frequencies and individual oscillator frequencies, defining the system. Quantum information processing could be a possible field of applicationComment: 5 page

Measurement, Decoherence and Chaos in Quantum Pinball

The effect of introducing measuring devices in a ``quantum pinball'' system is shown to lead to a chaotic evolution for the particle position as defined in Bohm's approach to Quantum Mechanics.Comment: Latex, uses ioplppt style, two figures. Also can be ftp'd anonymously from: ftp://zaphod.phys.port.ac.uk/pub/papers/paper2

Is Quantum Chaos Weaker Than Classical Chaos?

We investigate chaotic behavior in a 2-D Hamiltonian system - oscillators with anharmonic coupling. We compare the classical system with quantum system. Via the quantum action, we construct Poincar\'{e} sections and compute Lyapunov exponents for the quantum system. We find that the quantum system is globally less chaotic than the classical system. We also observe with increasing energy the distribution of Lyapunov exponts approaching a Gaussian with a strong correlation between its mean value and energy.Comment: text (LaTeX) + 7 figs.(ps

Quantum Chaos Versus Classical Chaos: Why is Quantum Chaos Weaker?

We discuss the questions: How to compare quantitatively classical chaos with quantum chaos? Which one is stronger? What are the underlying physical reasons

Exact field ionization rates in the barrier suppression-regime from numerical TDSE calculations

Numerically determined ionization rates for the field ionization of atomic hydrogen in strong and short laser pulses are presented. The laser pulse intensity reaches the so-called "barrier suppression ionization" regime where field ionization occurs within a few half laser cycles. Comparison of our numerical results with analytical theories frequently used shows poor agreement. An empirical formula for the "barrier suppression ionization"-rate is presented. This rate reproduces very well the course of the numerically determined ground state populations for laser pulses with different length, shape, amplitude, and frequency. Number(s): 32.80.RmComment: Enlarged and newly revised version, 22 pages (REVTeX) + 8 figures in ps-format, submitted for publication to Physical Review A, WWW: http://www.physik.tu-darmstadt.de/tqe

Computing the wavefunction from trajectories: particle and wave pictures in quantum mechanics and their relation

We discuss the particle method in quantum mechanics which provides an exact scheme to calculate the time-dependent wavefunction from a single-valued continuum of trajectories where two spacetime points are linked by at most a single orbit. A natural language for the theory is offered by the hydrodynamic analogy, in which wave mechanics corresponds to the Eulerian picture and the particle theory to the Lagrangian picture. The Lagrangian model for the quantum fluid may be developed from a variational principle. The Euler-Lagrange equations imply a fourth-order nonlinear partial differential equation to calculate the trajectories of the fluid particles as functions of their initial coordinates using as input the initial wavefunction. The admissible solutions are those consistent with quasi-potential flow. The effect of the superposition principle is represented via a nonclassical force on each particle. The wavefunction is computed via the standard map between the Lagrangian coordinates and the Eulerian fields, which provides the analogue in this model of Huygens principle in wave mechanics. The method is illustrated by calculating the time-dependence of a free Gaussian wavefunction. The Eulerian and Lagrangian pictures are complementary descriptions of a quantum process in that they have associated Hamiltonian formulations that are connected by a canonical transformation. The de Broglie-Bohm interpretation, which employs the same set of trajectories, should not be conflated with the Lagrangian version of the hydrodynamic interpretation. The theory implies that the mathematical results of the de Broglie-Bohm model may be regarded as statements about quantum mechanics itself rather than about its interpretation.Comment: 26 page

Die Anwendung des Multiple Sclerosis Functional Composite (MSFC) unter Berücksichtigung klinischer Parameter

$\textbf {Problem:}$ Die MS ist eine fluktuierende Erkrankung. Der MSFC wurde aus drei Tests für Arm- Bein und kognitive Funktion entwickelt. Untersucht wurde Durchführbarkeit, Korrelation mit Verlaufsform und Erkrankungsdauer und das Verhältnis zur EDSS. $\textbf {Methode:}$ 108 MS-Patienten führten den MSFC durch. Die Ergebnisse wurden mit EDSS-Werten, Verlaufsform und Erkrankungsdauer verglichen. $\textbf {Ergebnis:}$ Unterschiede bzgl. der Verlaufsform zeigen beide Tests signifikant. Mit der Erkrankungsdauer korrelierten der MSFC und die EDSS; Korrelation zwischen dem MSFC und der EDSS r=-0,51. $\textbf {Diskussion:}$ Der MSFC ist einfach durchzuführen, besitzt eine hohe Reliabilität und Validität. Der MSFC enthält neben der Beinfunktion Informationen über weitere Komponenten der MS. Der MSFC wird der Symptomvielfalt gerecht und reagiert sensitiver auf Veränderungen, daher Anwendung in Studien über kurze Zeit und in kleinen Kollektiven möglich. Anpassungsfähigkeit besteht durch den möglichen Austausch von Komponenten im Z-Score

Die Politik des Zeremoniells: Huldigungsfeiern im langen 19. Jahrhundert

Schwengelbeck M. Die Politik des Zeremoniells: Huldigungsfeiern im langen 19. Jahrhundert. Historische Politikforschung; 11. Frankfurt am Main: Campus-Verl.; 2007