Localized growth modes, dynamic textures, and upper critical dimension for the Kardar-Parisi-Zhang equation in the weak noise limit

A nonperturbative weak noise scheme is applied to the Kardar-Parisi-Zhang equation for a growing interface in all dimensions. It is shown that the growth morphology can be interpreted in terms of a dynamically evolving texture of localized growth modes with superimposed diffusive modes. Applying Derrick's theorem it is conjectured that the upper critical dimension is four.Comment: 10 pages in revtex and 2 figures in eps, a few typos correcte

Importance of bath dynamics for decoherence in spin systems

We study the decoherence of two coupled spins that interact with a chaotic spin-bath environment. It is shown that connectivity of spins in the bath is of crucial importance for the decoherence of the central system. The previously found phenomenon of two-step decoherence (Phys. Rev. Lett. {\bf 90}, 210401 (2003)) turns out to be typical for the bath with a slow enough dynamics or no dynamics. For a generic random system with chaotic dynamics a conventional exponential relaxation to the pointer states takes place. Our results confirm a conjecture of Paz and Zurek (Phys. Rev. Lett. {\bf 82}, 5181 (1999)) that for weak enough interactions the pointer states are eigenstates of the central system.Comment: submitted to Physical Review Letter

Remembering the bad old days: Human rights, economic conditions, and democratic performance in transitional regimes

Using the natural laboratory of 18 post-communist Central and Eastern European countries, this article presents a basic model for democratic transition, specifically testing two alternative explanations for the degree of citizen satisfaction with the performance of their fledgling democracies: 1) virtues of omission, which include bad actions from which the state refrains, namely violations of individual human rights, and 2) virtues of commission, which include positive state actions, in particular actions enhancing economic well-being. The findings clearly indicate that, during the transition period, citizens' sense of the condition of human rights is consistently more important than are perceived economic prospects as predictors of democratic performance. -- In der Untersuchung werden zwei alternative Hypothesen getestet, die den Grad der Zufriedenheit der Bürger mit der Performanz der Demokratie in 18 post-kommunistischen Ländern erklären sollen. Die eine Hypothese betont die Wichtigkeit der Garantie der individuellen Menschenrechte, die andere die Wichtigkeit der Verbesserung der ökonomischen Situation. In dem einen Fall soll sich der Staat menschenrechtsverletzender Handlungen enthalten (virtues of ommission), in dem anderen Fall soll er zur Hebung des wirtschaftlichen Wohlstands politisch eingreifen (virtues of commission). Der Befund zeigt, daß in der Übergangsperiode vom post-kommunistischen zum demokratischen Regime den Bürgern der Zustand der Menschenrechte für das Urteil über die Leistungsfähigkeit der Demokratie im eigenen Lande relativ wichtiger ist als die wirtschaftliche Entwicklung.

Democracy and its discontents in post-wall Germany

This paper traces the political behavior intentions of satisfied democrats, dissatisfied democrats, and non-democrats in western and eastern Germany. Dissatisfaction is most commonly expressed in support for the loyal opposition, with some minor tilt toward parties of the ends of the spectrum. Non-democrats, a very small percentage of the populace, more commonly express their disapproval through withdrawal rather than through active extremism. Based on a 1997 general population survey, the analysis reveals some differences in the magnitude of western versus eastern conceptions of the elements that make up democracy. But most of those differences get channeled into seemingly benign forms of political participation. The core of the findings is that dissatisfaction with democracy may well be a healthy stimulant rather than a threat to the vitality of either established or emerging democracies. -- Die hier vorgelegte Untersuchung analysiert politische Einstellungen und Verhaltensabsichten von zufriedenen Demokraten, unzufriedenen Demokraten und Nicht-Demokraten in Ost- und Westdeutschland. Unzufriedenheit mit der Politik führt in der Regel zu einer verstärkten Unterstützung demokratischer Oppositionsparteien, unter bestimmten Bedingungen aber auch zur Wahl extremer Oppositionsparteien. Die Untersuchung ergibt, dass Nicht-Demokraten, die in Ost- und Westdeutschland allerdings nur einen sehr geringen Prozentsatz ausmachen, ihre Unzufriedenheit weniger durch die Wahl einer extremen Partei, als durch einen Rückzug aus der Politik ausdrücken. Die Daten der repräsentativen Bevölkerungsumfrage zeigen in einigen Aspekten Unterschiede in bestimmten Wertorientierungen und im Demokratieverständnis der Ost- und der Westdeutschen. Daraus ergeben sich allerdings keine gravierenden Konsequenzen für den demokratischen Prozess. In beiden Teilen Deutschlands führen politische Unzufriedenheiten in aller Regel zur Wahl demokratischer Oppositionsparteien. Unzufriedenheit mit der Performanz des demokratischen Systems in Deutschland kann deshalb eher als Stimulus und weniger als Bedrohung der Demokratie interpretiert werden.

Hemidactylus mabouia

Number of Pages: 11Integrative BiologyGeological Science

Relaxation, thermalization and Markovian dynamics of two spins coupled to a spin bath

It is shown that by fitting a Markovian quantum master equation to the numerical solution of the time-dependent Schr\"odinger equation of a system of two spin-1/2 particles interacting with a bath of up to 34 spin-1/2 particles, the former can describe the dynamics of the two-spin system rather well. The fitting procedure that yields this Markovian quantum master equation accounts for all non-Markovian effects in as much the general structure of this equation allows and yields a description that is incompatible with the Lindblad equation.Comment: arXiv admin note: text overlap with arXiv:1605.0660

Spin generation away from boundaries by nonlinear transport

In several situations of interest, spin polarization may be generated far from the boundaries of a sample by nonlinear effects of an electric current, even when such a generation is forbidden by symmetry in the linear regime. We present an analytically solvable model where spin accumulation results from a combination of current gradients, nonlinearity, and cubic anisotropy. Further, we show that even with isotropic conductivity, nonlinear effects in a low symmetry geometry can generate spin polarization far away from boundaries. Finally, we find that drift from the boundaries results in spin polarization patterns that dominate in recent experiments on GaAs by Sih et al. [Phys. Rev. Lett. 97, 096605 (2006)]