Assessment of multireference approaches to explicitly correlated full configuration interaction quantum Monte Carlo.

The Full Configuration Interaction Quantum Monte Carlo (FCIQMC) method has proved able to provide near-exact solutions to the electronic Schrödinger equation within a finite orbital basis set, without relying on an expansion about a reference state. However, a drawback to the approach is that being based on an expansion of Slater determinants, the FCIQMC method suffers from a basis set incompleteness error that decays very slowly with the size of the employed single particle basis. The FCIQMC results obtained in a small basis set can be improved significantly with explicitly correlated techniques. Here, we present a study that assesses and compares two contrasting "universal" explicitly correlated approaches that fit into the FCIQMC framework: the [2]R12 method of Kong and Valeev [J. Chem. Phys. 135, 214105 (2011)] and the explicitly correlated canonical transcorrelation approach of Yanai and Shiozaki [J. Chem. Phys. 136, 084107 (2012)]. The former is an a posteriori internally contracted perturbative approach, while the latter transforms the Hamiltonian prior to the FCIQMC simulation. These comparisons are made across the 55 molecules of the G1 standard set. We found that both methods consistently reduce the basis set incompleteness, for accurate atomization energies in small basis sets, reducing the error from 28 mEh to 3-4 mEh. While many of the conclusions hold in general for any combination of multireference approaches with these methodologies, we also consider FCIQMC-specific advantages of each approach.Royal Societ

Inversionless gain in a three-level system driven by a strong field and collisions

Inversionless gain in a three-level system driven by a strong external field and by collisions with a buffer gas is investigated. The mechanism of populating of the upper laser level contributed by the collision transfer as well as by relaxation caused by a buffer gas is discussed in detail. Explicit formulae for analysis of optimal conditions are derived. The mechanism developed here for the incoherent pump could be generalized to other systems.Comment: RevTeX, 9 pages, 4 eps figure

An Integrative Design Framework for New Service Development

Service innovation is focused on customer value creation. At its core, customer-centric service innovation in an increasingly digital world is technology-enabled, human-centered, and process-oriented. This requires a cross-disciplinary, holistic approach to new service design and development (NSD). This paper proposes a new service strategy-aligned integrative design framework for NSD. It correlates the underlying theories and principles of disparate but interrelated aspects of service design thinking: service strategy, concept, design, experience and architecture into a coherent framework for NSD, consistent with the service brand value. Application of the framework to NSD is envisioned to be iterative and holistic, accentuated on continuous organizational and customer learning. The preliminary framework's efficacy is illustrated using a simplified telecom case example. © Springer International Publishing Switzerland 2014

National character research paradigms

The study objective is to analyze various approaches to the national identity problem.The leading research method is paradigmatic analysis of various conceptual and disciplinary approaches to the studies of both national character and identity of ethnic communities.As a result, the empirical and sociological paradigm stresses particular mechanisms of personal ethnic and national identification as well as the interaction of ethnic identity with other identity types, in particular social institutions and groups studied with the methods of experimental sociology. In conclusion, the integration function is the most adequate for interpretation of national identity under the philosophic and cultural paradigmEl objetivo del estudio es analizar diversos enfoques del problema de identidad nacional. El principal método de investigación es el análisis paradigmático de diversos enfoques conceptuales y disciplinarios para los estudios de carácter nacional e identidad de las comunidades étnicas. Como resultado, el paradigma empírico y sociológico acentúa los mecanismos particulares de identificación étnica y nacional personal, así como la interacción de la identidad étnica con otros tipos de identidad, en particular las instituciones sociales y los grupos estudiados con los métodos de la sociología experimental. En conclusión, la función de integración es la más adecuada para la interpretación de la identidad nacional bajo el paradigma filosófico y cultural