Pitfalls in the theory of carrier dynamics in semiconductor quantum dots: the single-particle basis vs. the many-particle configuration basis

We analyze quantum dot models used in current research for misconceptions that arise from the choice of basis states for the carriers. The examined models originate from semiconductor quantum optics, but the illustrated conceptional problems are not limited to this field. We demonstrate how the choice of basis states can imply a factorization scheme that leads to an artificial dependency between two, actually independent, quantities. Furthermore, we consider an open quantum dot-cavity system and show how the dephasing, generated by the dissipator in the von Neumann Lindblad equation, depends on the choice of basis states that are used to construct the collapse operators. We find that the Rabi oscillations of the s-shell exciton are either dephased by the dissipative decay of the p-shell exciton or remain unaffected, depending on the choice of basis states. In a last step we resolve this discrepancy by taking the full system-reservoir interaction Hamiltonian into account

09021 Abstracts Collection -- Software Service Engineering

From 04.01. to 07.01.2009, the Dagstuhl Seminar 09021 ``Software Service Engineering \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

06291 Abstracts Collection -- The Role of Business Processes in Service-Oriented Architectures

The Dagstuhl seminar on emph{The Role of Business Processes in Service Oriented Architectures} (Seminar 06291) took place in July 2006 (16.07.2006-21.07.2006 to be precise). The seminar was attended by more than 40 experts from both academia and industry. Unlike most Dagstuhl seminars there was a high participation from industry (in particular from organizations developing software, e.g., IBM, SAP, Microsoft, Google, etc.). The focal point of the seminar was the marriage of business processes and service oriented architectures. This was reflected by the topics selected by the participants and their background

Towards a flexible deployment of multi-cloud applications based on TOSCA and CAMP

Cloud Computing platforms offer diverse services and capabilities with own features. Hence, the provider services could be used by end users to compose a heterogeneous context of multiple cloud platforms in order to deploy their cloud applications made up of a set of modules, according to the best capabilities of the cloud providers. However, this is an ideal scenario, since the cloud platforms are being conducted in an isolated way by presenting many interoperability and portability restrictions, which complicate the integration of diverse provider services to achieve an heterogeneous deployment of multi-cloud applications. In this ongoing work, we present an approach based on model transformation to deploy multi-cloud applications by reusing standardization e orts related to the management and deployment of cloud applications. Specifically, using mechanisms speci ed by both standards, TOSCA and CAMP, we propose a methodology to describe the topology and distribution of modules of a cloud application and to deploy the interconnected modules over heterogeneous clouds. We illustrate our idea using a running example.Work partially supported by projects TIN2012-35669, funded by Spanish Ministry MINECO, FEDER; P11-TIC-7659 funded by Andalusian Gov; FP7-610531 SeaClouds funded by EU; and Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Intensity fluctuations in bimodal micropillar lasers enhanced by quantum-dot gain competition

We investigate correlations between orthogonally polarized cavity modes of a bimodal micropillar laser with a single layer of self-assembled quantum dots in the active region. While one emission mode of the microlaser demonstrates a characteristic s-shaped input-output curve, the output intensity of the second mode saturates and even decreases with increasing injection current above threshold. Measuring the photon auto-correlation function g^{(2)}(\tau) of the light emission confirms the onset of lasing in the first mode with g^{(2)}(0) approaching unity above threshold. In contrast, strong photon bunching associated with super-thermal values of g^{(2)}(0) is detected for the other mode for currents above threshold. This behavior is attributed to gain competition of the two modes induced by the common gain material, which is confirmed by photon crosscorrelation measurements revealing a clear anti-correlation between emission events of the two modes. The experimental studies are in excellent qualitative agreement with theoretical studies based on a microscopic semiconductor theory, which we extend to the case of two modes interacting with the common gain medium. Moreover, we treat the problem by an extended birth-death model for two interacting modes, which reveals, that the photon probability distribution of each mode has a double peak structure, indicating switching behavior of the modes for the pump rates around threshold.Comment: 11 pages, 5 figures, submitted to Phys. Rev.

10021 Abstracts Collection -- Service-Oriented Architecture and (Multi-)Agent Systems Technology

From 10.01. to 15.01.2010, Dagstuhl Seminar 10021 ``Service-Oriented Architecture and (Multi-)Agent Systems Technology \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available