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We numerically demonstrate so-far undescribed features in ionization and high harmonic generation from bound states with nonvanishing electronic angular momentum. The states' modified response to a strong laser pulse can be exploited for novel measurement and pulse production schemes. It is shown that angularly asymmetric tunneling from the states can be mapped onto variations of high harmonic intensities and that near-circularly polarized isolated attosecond extreme ultraviolet or x-ray pulses can be produced.

Electric ring currents ${I}_{nlm}$ and corresponding magnetic fields ${\mathbf{B}}_{nlm}$ exist in atomic orbitals ${\ensuremath{\psi}}_{nlm}$ $(m\ensuremath{\ne}0)$. Simple expressions are derived for ${I}_{nlm}$ and for ${\mathbf{B}}_{nlm}(\mathbf{r}=\mathbf{0})$ at the nucleus. The magnitude of ${I}_{nlm}$ depends only on $n$ and decreases with increasing quantum number $n$. In contrast, ${\mathbf{B}}_{nlm}(\mathbf{r}=\mathbf{0})$ decreases with increasing quantum numbers $n$ and $l$ but increases with $m$. The largest magnitudes of the electric ring currents and induced magnetic fields are thus obtained for $2{p}_{\ifmmode\pm\else\textpm\fi{}1}$ orbitals. Moreover, ${I}_{nlm}$ and ${\mathbf{B}}_{nlm}(\mathbf{r}=\mathbf{0})$ increase with the nuclear charge $Z$ as ${Z}^{2}$ and ${Z}^{3}$, respectively. Simple circularly polarized $\ensuremath{\pi}$ laser pulses are designed for complete population transfers from $1s$ to target $2{p}_{\ifmmode\pm\else\textpm\fi{}1}$ orbitals. The corresponding solutions of the time-dependent Schr\"odinger equation for the hydrogen atom H $(Z=1)$ imply equivalent solutions for arbitrary $Z$, by means of simple scaling laws for the time $(1∕{Z}^{2})$, frequency $({Z}^{2})$, and field strength $({Z}^{3})$ or intensity $({Z}^{6})$. For example, the parameters of the $\ensuremath{\pi}$ pulse for H (pulse duration $\ensuremath{\tau}=115\phantom{\rule{0.3em}{0ex}}\mathrm{fs}$, maximum intensity ${\mathcal{I}}_{\mathrm{max}}=1.47\ifmmode\times\else\texttimes\fi{}{10}^{10}\phantom{\rule{0.3em}{0ex}}\mathrm{W}\phantom{\rule{0.2em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$) are scaled to values $\ensuremath{\tau}=679$ as and ${\mathcal{I}}_{\mathrm{max}}=7.09\ifmmode\times\else\texttimes\fi{}{10}^{16}\phantom{\rule{0.3em}{0ex}}\mathrm{W}\phantom{\rule{0.2em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$ for ${\mathrm{Al}}^{12+}$, inducing the giant magnetic field $\ensuremath{\mid}{\mathbf{B}}_{21\ifmmode\pm\else\textpm\fi{}1}(\mathbf{r}=\mathbf{0})\ensuremath{\mid}=1146\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. The results for hydrogenlike atoms allow corresponding estimates of electric ring currents and magnetic fields in molecules, where molecular orbitals are expressed as linear combinations of atomic orbitals.

We numerically demonstrate so-far undescribed features in ionization and high harmonic generation from bound states with nonvanishing electronic angular momentum. The states' modified response to a strong laser pulse can be exploited for novel measurement and pulse production schemes. It is shown that angularly asymmetric tunneling from the states can be mapped onto variations of high harmonic intensities and that near-circularly polarized isolated attosecond extreme ultraviolet or x-ray pulses can be produced.

A circularly polarized ultraviolet (UV) laser pulse may excite a unidirectional valence-type electronic ring current in an oriented molecule, within the pulse duration of a few femtoseconds (e.g., tau = 3.5 fs). The mechanism is demonstrated by quantum model simulation for |X = |1(1)A(1g) --> |E(+) = |4 (1)E(u+) population transfer in the model system, Mg-porphyrin. The net ring current generated by the laser pulse (I = 84.5 microA) is at least 100 times stronger than any ring current, which could be induced by means of permanent magnetic fields, with present technology.

Simulations of the electronic wavepacket dynamics driven by circularly polarized laser pulses with durations τ I max 12 Wcm −2 demonstrate ignition of electron circulation in the oriented ring-shaped molecule, Mg-porphyrin. This chapter designs laser pulses for perfectly periodic electron circulation. Starting from nonperfect so-called π and π/ 2 laser pulses for reference, the goal is achieved by re-optimized π/ 2 laser pulses, which yield half population transfer from the ground state to a selective component of excited degenerate states with E symmetry. The resulting period of electron circulation is determined by a Heisenberg type relation in terms of the energy gap. Various approaches to these laser pulses are compared. By extension, combinations of sequential re-optimized pulses yield selective electron circulations represented by analogous hybrid states, which consist of two components with different periods.

Distributed multimedia applications require negotiation of quality of service (QoS) and resource reservation for distributed application parts and communication links. Negotiation of QoS is a balancing process between the QoS specified by a client, the resource availabilities of the distributed system and the functional capabilities of the distributed application. Negotiation requires application level QoS descriptions and an end to end view spanning the whole distributed application. NRP is an application level protocol meeting these requirements. NRP performs negotiation based on client specified QoS value ranges and given resource availability on endsystems and communication links. NRP is independent of application level QoS semantics. It allows QoS negotiation and resource reservation in three phases and supports a wide range of distributed application topologies.

We apply the time-dependent analytical R-matrix theory to develop a movie of hole motion in a Kr atom upon ionization by strong circularly polarized field. We find rich hole dynamics, ranging from rotation to swinging motion. The motion of the hole depends on the final energy and the spin of the photoelectron and can be controlled by the laser frequency and intensity. Crucially, hole rotation is a purely non-adiabatic effect, completely missing in the framework of quasistatic (adiabatic) tunneling theories. We explore the possibility to use hole rotation as a clock for measuring ionization time. Analysing the relationship between the relative phases in different ionization channels we show that in the case of short-range electron-core interaction the hole is always initially aligned along the instantaneous direction of the laser field, signifying zero delays in ionization. Finally, we show that strong-field ionization in circular fields creates spin currents (i.e. different flow of spin-up and spin-down density in space) in the ions. This phenomenon is intimately related to the production of spin-polarized electrons in strong laser fields [Barth I and Smirnova O 2013 Phys. Rev. A 88 013401]. We demonstrate that rich spin dynamics of electrons and holes produced during strong field ionization can occur in typical experimental conditions and does not require relativistic intensities or strong magnetic fields.

We verify the theory of nonadiabatic ionization of degenerate valence orbitals in strong circularly polarized laser fields by numerically solving the two-dimensional time-dependent Schrodinger equation for an effective one-electron potential of neon. The numerically calculated ionization ratios of the and orbitals agree well with the theoretical results (i.e., the counter-rotating electron tunnels more easily). However, for strong laser pulses and low laser frequencies, the adiabatic laser-dressed orbitals play an important role. In a Floquet treatment of a three-level model, we find that in this regime the ionization ratio of initial and orbitals depends strongly on the orbital energy order of valence s and orbitals. We also show that the emission angles of valence and electrons are different and should be observable in attoclock experiments.

Distributed multimedia systems require quality of service at various abstraction levels. At the application level, QoS describes communication in terms of application specific processing units, e.g. frames. At the transport level QoS is used to describe the communication load for the transport system. An architecture integrating the various levels is presented. The architecture provides the framework for performing negotiation of QoS and resource reservation. It includes the specification of a programmer interface and a flowspec carrying QoS information between communication nodes.

Die Erstellung verteilter Multimedia-Anwendungen setzt leistungsfahige Entwicklungsplattfonnen voraus, innerhalb deren Probleme wie die Ubertragung multimedialer Daten, die Gewahrleistung der Dienstgute durch Reservierung von Ressourcen und die Synchronisation von Datenstromen gelost werden. Cinema (Configurable INtEgrated Multimedia Architecture) bietet als eine solche Entwicklungsplattform Abstraktionen zur Nutzung multimedialer Systemdienste an, womit funktionale Bearbeitungseinheiten erstellt, komplexe Verarbeitungstopologien in verteilten Systemen aufgebaut und unter Einhaltung von Synchronisations- und Dienstgute-Spezifikationen gesteuert werden konnen. In diesem Papier werden nach einem kurzen Uberblick uber die Abstraktionen der Cinema-Dienstschnittstelle die internen Strukturen und Ablaufe vorgestellt, mit denen die Multimedia-Dienste in verteilten Systemen erbracht werden.

Distributed multimedia applications combine the advantage of distributed computing with the capability of processing discrete and continuous media in an integrated fashion. The development of multimedia applications in distributed environments requires specific abstractions and services, which are usually not provided by generic operating systems. These services are typically realized by software components, often referred to as middleware.

We relate powers of trigonometric functions to Gaussians by proving that properly truncated cosn functions converge to a Gaussian as n tends to infinity. For an application, we analyse the laser-induced population transfer |X1Σ+ → |A1Πx in a two-level model system of aluminium monochloride (AlCl) with fixed nuclei. We apply linearly x-polarized ultraviolet laser pulses with a trigonometric envelope function, whose square has full width at half-maximum of 2.5 fs and 5.0 fs. Studying population dynamics and optimized laser parameters, we find that the optimal field amplitude for trigonometric pulses with n = 20 and n = 1000 has a relative difference of 1%, which is below experimental resolution.

In a two-part theoretical study, field-free orientation of OHF(-) is achieved by means of moderately intense half-cycle, infrared laser pulses. In the first step, a short linearly polarized pulse excites a superposition of rigid rotor rotational eigenstates via interaction with the permanent dipole moment of OHF(-). After the field has been switched off, pronounced molecular orientation is observed for several picoseconds. In the second step, femtosecond few-cycle laser pulses are applied to the oriented system to steer vibrational dynamics, modeled by anharmonic vibrational wave functions calculated on a potential energy surface obtained with unrestricted fourth order Moller-Plesset ab initio calculations. The result is selective bond breaking of OHF, followed by the spatial separation of dissociation products in the space-fixed frame. Due to revivals in the rotational wavepacket, product yields can be enhanced over long times.