Rabi oscillations and macroscopic quantum superposition states

A two-level atom interacting with a single radiation mode is considered, without the rotating-wave approximation, in the strong coupling regime. It is shown that, in agreement with the recent results on Rabi oscillations in a Josephson junction (Y. Nakamura, Yu. A. Pashkin and J. S. Tsai, Phys. Rev. Lett. {\bf 87}, 246601 (2001)), the Rabi frequency is indeed proportional to first kind integer order Bessel functions in the limit of a large number of photons and the dressed states are macroscopic quantum superposition states. To approach this problem analytically use is made of the dual Dyson series and the rotating-wave approximation.Comment: 7 pages, revtex, no figures. I have to thank Kazuyuki Fujii for pointing me out some corrections to introduce into the paper. Besides, the title and the nomenclature has been changed in agreement to editorial requirements. Finally, the correct citation for the paper by Nakamura et al. has been introduce

Neutron and gamma irradiation effects on power semiconductor switches

The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation

Event-sequences, plots and narration in computer games

Starting with the debate between ludologists and narratologists this essay tries to show that there is a narrative aspect in computer games which has nothing to do with background stories and cut scenes. A closer analysis of two sequences, taken from the MMORPG Everquest II and the adventure game Black Mirror, is the basis for a distinction between three aspects of this kind of narrative in computer games: the sequence of activities of the player, the sequence of events as it is determined by the mechanics of the game and this sequence of events understood as a plot, that is as a sequence of chronologically ordered and causally linked events. This kind of narrative is quite distant to the prototypical narrative which is the basis of most of the narratology. But actually all media, not only computer games, need their own narratology

Monitoring data in R with the lumberjack package

Monitoring data while it is processed and transformed can yield detailed insight into the dynamics of a (running) production system. The lumberjack package is a lightweight package allowing users to follow how an R object is transformed as it is manipulated by R code. The package abstracts all logging code from the user, who only needs to specify which objects are logged and what information should be logged. A few default loggers are included with the package but the package is extensible through user-defined logger objects.Comment: Accepted for publication in the Journal of Statistical Softwar

Videogames in the museum:participation, possibility and play in curating meaningful visitor experiences

In 2014 Videogames in the Museum [1] engaged with creative practitioners, games designers, curators and museums professionals to debate and explore the challenges of collecting and exhibiting videogames and games design. Discussions around authorship in games and games development, the transformative effect of the gallery on the cultural reception and significance of videogames led to the exploration of participatory modes and playful experiences that might more effectively expose the designer’s intent and enhance the nature of our experience as visitors and players. In proposing a participatory mode for the exhibition of videogames this article suggests an approach to exhibition and event design that attempts to resolve tensions between traditions of passive consumption of curated collections and active participation in meaning making using theoretical models from games analysis and criticism and the conceit of game and museum spaces as analogous rules based environments