Characterization and Control of Quantum Spin Chains and Rings

Information flow in quantum spin networks is considered. Two types of control -- temporal bang-bang switching control and control by varying spatial degrees of freedom -- are explored and shown to be effective in speeding up information transfer and increasing transfer fidelities. The control is model-based and therefore relies on accurate knowledge of the system parameters. An efficient protocol for simultaneous identification of the coupling strength and the exact number of spins in a chain is presented.Comment: to appear in ISCCSP 201

Das duale Prozessmodell dynamischer Fähigkeiten: (Mikro)-Politische Desiderata und Rekonstruktionsperspektiven

Das duale Prozessmodell dynamischer Fähigkeiten von Schreyögg und Kliesch-Eberl (2007) ist eine interessante Alternative zu Routine- oder Integrationsmodellen dynamischer Fähigkeiten. Das Modell bietet bislang jedoch nur eine funktionalistisch eingeschränkte Interpretation politischer Prozesse, die für das Verständnis dynamischer Fähigkeiten von großer Relevanz sind. Der vorliegende Beitrag zeigt, wie mit verschiedenen Politikkonzeptionen das Potential des dualen Prozessmodells dynamischer Fähigkeiten zur Wirklichkeitserschließung in dieser Hinsicht erweitert werden kann. Damit soll auch zur differenzierteren Reflektion machtpolitischer Probleme im Diskurs um dynamische Fähigkeiten angeregt werden.The dual process model of dynamic capabilities (Schreyögg & Kliesch-Eberl, 2007) offers a promising alternative to routine based and integrative models of dynamic capabilities. However, the model does not sufficiently theorize political phenomena, being considered here as crucial organizational phenomena to be explained by any dynamic capability framework. Therefore, this paper shows how the related explorative potential of the dual process model can be enhanced by means of political concepts, encompassing the individual, group and organizational level of analysis. Thereby, this paper contributes to a more nuanced reflection of political phenomena interwoven with dynamic capabilities, going beyond the predominantly functional interpretation of politics and power included in the dual process model

Chromospherically active stars in the ROTSE-1 database: paper 6. Variables 126 - 149

Another 24 new chromospherically active stars are presented, which were found in the ROTSE-1 database: GSC 02268-00394, GSC 01224-00894, GSC 00648-00579, GSC 02865-01987, GSC 01851-01202, GSC 00124-00551, GSC 00150-01109, GSC 01339-00572, GSC 02968-01511, GSC 03005-00885, GSC 01083-00698, GSC 03941-00354, GSC 04450-00134, GSC 05163-01764, GSC 01095-00848, GSC 04459-00659, USNO A2.0 1275-14029063, GSC 04247-00903, GSC 01656-01276, GSC 02197-01430, GSC 02227-01294, GSC 04480-00965, GSC 01159-00245, GSC 02237-01574. For one of these stars (GSC 00124-00551), further observations were made using a TeleView 509/5.0 telescope with a CCD camera SIGMA1603 and IR-cutting filter in Velden, Germany

Reflexive Power(s)? - Exploring the Dynamics, Contradictions and Paradoxes of Evolving Political Forms in Innovative Organizations.: Paper presented at the EGOS Colloquium 2009, Barcelona, July 2-4, 2009; Sub-theme 19: Power, resistance and hegemony in the contexts of organizational and institutional change

How do reflexive political forms within organizations and the design of innovation processes co-evolve? This paper focuses on emerging reflexive forms of power and authority, considered as regimes beyond pure domination (Clegg et al. 2006: 330 f.). We assume that preserving freedom and initiative of individuals, while not undermining the power of organizational top elites, is particularly essential for business success of organisations operating in high-tech, innovative sectors. Up to now, however, neither the development of related political forms within organisations, nor their intertwinements with innovation processes have been very well understood. Therefore this paper studies the linkages between innovation processes and reflexive political forms of organizations. More specifically, the paper aims to explore in detail the contested, antagonistic and paradoxical processes an organisation must undertake in designing a reflexive political form, a “political hybrid” (Clegg et al. 2006: 333), conducive to innovation capabilities and innovation processes in high-tech companies. Theoretical reasoning is underlined by first insights from a longitudinal case study, being part of a comparative case study program, focusing on the co-evolution of political forms and innovation process design in a SME in southern Germany. The paper contributes to the debate on power and innovation in several respects. First, we will propose a dynamic approach to exploring change and development of political forms within organisations. Most of the literature concerned with different political forms and political regimes within organisations is still centred on static typologies and its comparison (Clegg et al. 2006: 332). Second, we will examine the often neglected, contradictory processes shaping hybrid political forms in organisations. Third, we will conceptually and empirically explore linkages between innovation processes and emerging political hybrids within organizations. This study is, to the best of our knowledge, a research desideratum both in the literature on power and the literature on innovation processes (e.g. Hage and Meeus 2006; Poole and Van De Ven 2004; Vigoda-Gadot and Drory 2006; Clegg et al. 2006)

Management contra "Neue Managementkonzepte"? Gleichzeitig Anmerkungen zur betriebspolitisch marginalisierten Bedeutung von Sprecherausschüssen in Reorganisationsprozessen

"Die Umsetzung von 'neuen Managementkonzepten' wie Lean Production oder Lean Management bedeutet die Selbstanwendung von Rationalisierungs- und Effektivierungsbestrebungen auf das Management als Institution - also auf die Personen die Managementfunktionen ausüben. Funktionale Erfordernisse 'neuer Managementkonzepte' und betriebspolitisch verankerte Interessen von Managern können dabei in Konflikt geraten. Die Umsetzbarkeit 'neuer Managementkonzepte' hängt dann wesentlich von den betriebspolitischen Konstellationen im Management und deren Beeinflussung im Umsetzungsprozeß ab. Auf dieser konezptionellen Folie wird anhand von sechs Intensivfallstudien in deutschen Unternehmungen der Umsetzungsprozeß von Enthierarchisierungs- und Dezentralisierungsmaßnahmen rekonstruiert. Darüber hinaus wird der Versuch unternommen, für den Umsetzungsprozeß 'erfolgskritische' Aktivitäten zu erkennen." (Autorenreferat, IAB-Doku

Structured Singular Value Analysis for Spintronics Network Information Transfer Control

Control laws for selective transfer of information encoded in excitations of a quantum network, based on shaping the energy landscape using time-invariant, spatially-varying bias fields, can be successfully designed using numerical optimization. Such control laws, already departing from classicality by replacing closed-loop asymptotic stability with alternative notions of localization, have the intriguing property that for all practical purposes they achieve the upper bound on the fidelity, yet the (logarithmic) sensitivity of the fidelity to such structured perturbation as spin coupling errors and bias field leakages is nearly vanishing. Here, these differential sensitivity results are extended to large structured variations using $\mu$-design tools to reveal a crossover region in the space of controllers where objectives usually thought to be conflicting are actually concordant

Sensitivity and Robustness of Quantum Spin-1/2 Rings to Parameter Uncertainty

Selective transfer of information between spin-1/2 particles arranged in a ring is achieved by optimizing the transfer fidelity over a readout time window via shaping, externally applied, static bias fields. Such static control fields have properties that clash with the expectations of classical control theory. Previous work has shown that there are cases in which the logarithmic differential sensitivity of the transfer fidelity to uncertainty in coupling strength or spillage of the bias field to adjacent spins is minimized by controllers that produce the best fidelity. Here we expand upon these examples and examine cases of both classical and non-classical behavior of logarithmic sensitivity to parameter uncertainty and robustness as measured by the p function for quantum systems. In particular we examine these properties in an 11-spin ring with a single uncertainty in coupling strength or a single bias spillage

Strong gametocytocidal effect of methylene blue-based combination therapy against falciparum malaria

With the availability of new preventive and curative interventions, global malaria control has been strengthened significantly in recent years. Drugs effective in reducing malaria gametocytaemia might contribute to local elimination and possible long-term eradication. We here report on the effects of methylene blue (MB)-based malaria combination therapy on gametocytaemia during a randomised-controlled trial in Burkina Faso. An open-label randomised controlled phase II study in 180 children aged 6-10 years with uncomplicated falciparum malaria was conducted in Nouna, north-western Burkina Faso. Children were randomised to MB-artesunate (AS), MB-amodiaquine (AQ), and AS-AQ (local standard of care). Overall follow-up was for 28 days, follow-up for gametocytaemia was for 14 days. The treatment groups were similar in baseline characteristics and there was only one loss to follow-up. Compared to AS-AQ, both MB-containing regimens were associated with significantly reduced gametocyte carrier rates during follow-up days 3, 7, and 14. This effect was seen both in patients with and without P. falciparum gametocytaemia at baseline. MB reveals pronounced gametocytocidal activity which appears to act against both existing and developing P. falciparum gametocytes. MB-based combination therapy thus has the potential to reduce transmission of P. falciparum malaria in endemic regions, which has important implications for future elimination and eradication strategies

Spin recovery in the 25nm gate length InGaAs field effect transistore

We augmented an ensemble Monte-Carlo semiconductor device simulator [3] to incorporate electron spin degrees of freedom using a Bloch equation model to investigate the feasibility of spintronic devices. Results are presented for the steady state polarization and polarization decay due to scattering and spin orbit coupling for a III-V MOSFET device as a function of gate voltages, injection polarization and strain