Computational Tools for Cohomology of Toric Varieties

In this review, novel non-standard techniques for the computation of cohomology classes on toric varieties are summarized. After an introduction of the basic definitions and properties of toric geometry, we discuss a specific computational algorithm for the determination of the dimension of line-bundle valued cohomology groups on toric varieties. Applications to the computation of chiral massless matter spectra in string compactifications are discussed and, using the software package cohomCalg, its utility is highlighted on a new target space dual pair of (0,2) heterotic string models.Comment: 17 pages, 4 tables; prepared for the special issue "Computational Algebraic Geometry in String and Gauge Theory" of Advances in High Energy Physics, cohomCalg implementation available at http://wwwth.mppmu.mpg.de/members/blumenha/cohomcalg

Gospodarstvo viđeno kroz orijentaciju prema subjektu u socijalnim ustanovama

People would like to work and have their part in the society. Working means paying taxes,paying dues to social insurance and to have a job for earning and living. Is this really all of it? Does individual work just fulfill the entire concept of a welfare state and to make money? A Job is more than the pure earning and living. It is a central part of a person’s life and so it is a part of self-fulfillment and self-efficacy in a human’s life. But there are challenges for social organizations to face. First there are clients who need a service on the other hand the social worker as subject in a working environment. Social work is always in a contradiction between the client as a customer and working on a “normal” market for social services. So if there is a market all economic rules of this market are also counting for organizations of social work. This crosswalk can be done by a subject-orientated view for the social worker as a self-realization human with personnel development and also for the clients who need individualized services for their special needs. Social work must give up fiscal accounting and use economic instruments to work on a market and to match with other organizations on the same market. So the services become more transparent for the clients and the organization becomes attractive to a competent social worker.Ljudi bi željeli raditi i imati svoju ulogu u društvu. Raditi znači plaćati porez, plaćati doprinos za socijalno osiguranje i imati posao kojim će zarađivati za život. Je li to zaista sve? Radi li čovjek zaista samo da bi ispunio koncept socijalne države i zaradio? Posao je više od puke zarade za život. To je središnja točka čovjekova postojanja pa je time i dio samoispunjenja i samoučinkovitosti u ljudskom životu. No, treba se suočiti s izazovima društvenih organizacija. U socijalnom radu prije svega, postoje korisnici koji trebaju usluge, a s druge strane je socijalni radnik kao subjekt u radnom okruženju. Socijalni rad je uvijek u proturječju između korisnika kao kupca i rada na “normalnom” tržištu društvenih usluga. Dakle, postoji li tržište, sva ekonomska pravila toga tržišta vrijede i za organizacije socijalnog rada. Prijelaz k takvom stanju odnosa bi omogućilo stajalište orijentirano na subjekta socijalnog radnika kao samoostvarenog čovjeka s osobnim razvojem i stručnjaka za korisnike koji trebaju individualizirane usluga za svoje posebne potrebe. Socijalni rad mora odustati od fiskalnog računovodstva i koristiti ekonomske instrumente djelovanja na tržištu kako bi se uskladio s drugim organizacijama na istom tržištu. Tako bi usluge postale korisnicima transparentnije, a organizacija atraktivna kompetentnom socijalnom radniku

Cohomology of Line Bundles: A Computational Algorithm

We present an algorithm for computing line bundle valued cohomology classes over toric varieties. This is the basic starting point for computing massless modes in both heterotic and Type IIB/F-theory compactifications, where the manifolds of interest are complete intersections of hypersurfaces in toric varieties supporting additional vector bundles.Comment: 11 pages, 1 figure, 2 tables; v2: typos and references corrected; v3: proof-related statements updated, cohomCalg implementation available at http://wwwth.mppmu.mpg.de/members/blumenha/cohomcalg

Low-temperature DC conductivity of LiNbO 3 single crystals

We report on conductivity measurements of LiNbO3 single crystals with congruent composition in ambient atmosphere between 449 and 727 K which include the lowest temperatures covered so far. The ionic DC conductivity observed along the c-axis at, e. g., 650 K is 6.7 × 10-9 S/cm and shows an activation energy of 1.33 eV. The corresponding Li+ diffusion coefficients range between 2.5 × 10-22 and 1.4 × 10-16 m2/s. These results are perfectly consistent with our conductivity results in the high-temperature regime as well as SIMS measurements published recently (Rahn et al., Phys. Chem. Chem. Phys. 14 (2012) 2427). From the Li+ diffusion coefficients obtained here a Haven ratio of 0.7(2) can be deduced. © by Oldenbourg Wissenschaftsverlag, München

Familien an der Goethe-Universität : Angebote für Studierende und Beschäftigte

Die Goethe-Universität Frankfurt am Main verpflichtet sich der Familienfreundlichkeit als eines der zentralen Querschnittsthemen der Universität. Ziel ist es, in Studium, Forschung, Lehre und Verwaltung nachhaltig bessere Rahmenbedingungen für Hochschulmitglieder mit Familienaufgaben zu schaffen. Familie umfasst dabei über die klassische Kernfamilie hinaus alle Lebensgemeinschaften, in denen eine langfristige soziale Verantwortung für andere wahrgenommen wird. ..

Self-diffusion of lithium in amorphous lithium niobate layers

We investigated lithium self-diffusion in amorphous lithium niobate layers between 298 and 423 K. For the experiments, amorphous 6LiNbO 3/ 7LiNbO 3 isotope hetero-structures were deposited by ion beam sputtering and analysed after diffusion annealing by secondary ion mass spectrometry (SIMS). This arrangement allows one to study pure isotope interdiffusion. The results show that the diffusivities obey the Arrhenius law with an activation enthalpy of 0.7 eV, which is considerably lower than the activation enthalpy found for LiNbO 3 single crystals in literature. Consequently, the Li diffusivities are higher by at least eight orders of magnitude in the amorphous samples in the temperature range studied. © by Oldenbourg Wissenschaftsverlag, München

Exact Performance of Concatenated Quantum Codes

When a logical qubit is protected using a quantum error-correcting code, the net effect of coding, decoherence (a physical channel acting on qubits in the codeword) and recovery can be represented exactly by an effective channel acting directly on the logical qubit. In this paper we describe a procedure for deriving the map between physical and effective channels that results from a given coding and recovery procedure. We show that the map for a concatenation of codes is given by the composition of the maps for the constituent codes. This perspective leads to an efficient means for calculating the exact performance of quantum codes with arbitrary levels of concatenation. We present explicit results for single-bit Pauli channels. For certain codes under the symmetric depolarizing channel, we use the coding maps to compute exact threshold error probabilities for achievability of perfect fidelity in the infinite concatenation limit.Comment: An expanded presentation of the analytic methods and results from quant-ph/0111003; 13 pages, 6 figure