eSciDoc Infrastructure: a Fedora-based e-Research Framework

4th International Conference on Open RepositoriesThis presentation was part of the session : Fedora User Group PresentationsDate: 2009-05-20 03:30 PM – 05:00 PMeSciDoc is the open-source e-Research environment jointly created by the German Max Planck Society and FIZ Karlsruhe. It consists of a generic set of basic services ("eSciDoc Infrastructure") and various applications built on top of this infrastructure ("eSciDoc Solutions"). This presentation will focus on the eSciDoc Infrastructure, highlight the differences to the underlying Fedora repository, and demonstrate its powerful und application-centric programming model. In the end of 2008, we released version 1.0 of the eSciDoc Infrastructure. Digital Repositories undergo yet again a substantial change of paradigm. While they started several years ago with a library perspective, mainly focusing on publications, they are now becoming more and more a commodity tool for the workaday life of researchers. Quite often the repository itself is just a background service, providing storage, persistent identification, preservation, and discovery of the content. It is hidden from the end-user by means of specialized applications or services. Fedora's approach of providing a repository architecture rather than an end-user tool accommodates well to this evolution. eSciDoc, from the start of the project nearly five years ago, has emphasized this design pattern by separating backend services (eSciDoc Infrastructure) and front-end applications (eSciDoc Solutions)

A quenched large deviation principle in a continuous scenario

We prove the analogue for continuous space-time of the quenched LDP derived in Birkner, Greven and den Hollander (2010) for discrete space-time. In particular, we consider a random environment given by Brownian increments, cut into pieces according to an independent continuous-time renewal process. We look at the empirical process obtained by recording both the length of and the increments in the successive pieces. For the case where the renewal time distribution has a Lebesgue density with a polynomial tail, we derive the quenched LDP for the empirical process, i.e., the LDP conditional on a typical environment. The rate function is a sum of two specific relative entropies, one for the pieces and one for the concatenation of the pieces. We also obtain a quenched LDP when the tail decays faster than algebraic. The proof uses coarse-graining and truncation arguments, involving various approximations of specific relative entropies that are not quite standard. In a companion paper we show how the quenched LDP and the techniques developed in the present paper can be applied to obtain a variational characterisation of the free energy and the phase transition line for the Brownian copolymer near a selective interface

Complete algebraic vector fields on affine surfaces

Let \AAutH (X) be the subgroup of the group \AutH (X) of holomorphic automorphisms of a normal affine algebraic surface $X$ generated by elements of flows associated with complete algebraic vector fields. Our main result is a classification of all normal affine algebraic surfaces $X$ quasi-homogeneous under \AAutH (X) in terms of the dual graphs of the boundaries \bX \setminus X of their SNC-completions \bX.Comment: 44 page

Mutual information in classical spin models

The total many-body correlations present in finite temperature classical spin systems are studied using the concept of mutual information. As opposed to zero-temperature quantum phase transitions, the total correlations are not maximal at the phase transition, but reach a maximum in the high temperature paramagnetic phase. The Shannon and Renyi mutual information in both Ising and Potts models in 2 dimensions are calculated numerically by combining matrix product states algorithms and Monte Carlo sampling techniques

Controlled nonuniformity in macroporous silicon pore growth

Photoelectrochemical etching of uniform prestructured silicon wafers in hydrofluoric acid containing solutions yields periodic structures that can be applied to two- and three-dimensional photonic crystals or microfluidics. Here we demonstrate experimentally macroporous silicon etching initiated by a nonuniform predefined lattice. For conveniently chosen parameters we observe a stable growth of pores whose geometrical appearance depends strongly on the spatially different nucleation conditions. Moreover, we show preliminary results on three-dimensionally shaped pores. This material can be used to realize hybrid photonic crystal structures and incorporate waveguides in three-dimensional photonic crystals

Dynamical and Topological Properties of the Kitaev Model in a [111] Magnetic Field

The Kitaev model exhibits a Quantum Spin Liquid hosting emergent fractionalized excitations. We study the Kitaev model on the honeycomb lattice coupled to a magnetic field along the [111] axis. Utilizing large scale matrix product based numerical models, we confirm three phases with transitions at different field strengths depending on the sign of the Kitaev exchange: a non-abelian topological phase at low fields, an enigmatic intermediate regime only present for antiferromagnetic Kitaev exchange, and a field-polarized phase. For the topological phase, we numerically observe the expected cubic scaling of the gap and extract the quantum dimension of the non-Abelian anyons. Furthermore, we investigate dynamical signatures of the topological and the field-polarized phase using a matrix product operator based time evolution method.Comment: Changed convention to be in accordance with published articl