Finding Traps in Non-linear Spin Arrays

Precise knowledge of the Hamiltonian of a system is a key to many of its applications. Tasks such state transfer or quantum computation have been well studied with a linear chain, but hardly with systems, which do not possess a linear structure. While this difference does not disturb the end-to-end dynamics of a single excitation, the evolution is significantly changed in other subspaces. Here we quantify the difference between a linear chain and a pseudo-chain, which have more than one spin at some site (block). We show how to estimate a number of all spins in the system and the intra-block coupling constants. We also suggest how it is possible to eliminate excitations trapped in such blocks, which may disturb the state transfer. Importantly, one uses only at-ends data and needs to be able to put the system to either the maximally magnetized or the maximally mixed state. This can obtained by controlling a global decoherence parameter, such as temperature.Comment: 5 pages, 1 figur

Ferromagnetism in UGe2 : A microscopic model

Anderson lattice model is used to rationalize the principal features of the heavy fermion compound UGe2 by means of the generalized Gutzwiller approach (the SGA method). This microscopic approach successfully reproduces magnetic and electronic properties of this material, in a qualitative agreement with experimental findings from the magnetization measurements, the neutron scattering, and the de Haas-van Alphen oscillations. Most importantly, it explains the appearance, sequence, character, and evolution in an applied magnetic field of the observed in UGe2 ferro- and, para-magnetic phases as an effect of a competition between the f-f electrons Coulomb interaction energy and f-conduction electrons kinetic energy (hybridization)Comment: submitted to Phys. Rev.

Criticalities in the itinerant ferromagnet UGe2_{2}

We provide a microscopic description of the magnetic properties of UGe$_2$ and in particular, of its both classical and quantum critical behavior. Namely, we account for all the critical points: the critical ending point (CEP) at the metamagnetic phase transition, the tricritical point, and the quantum critical end point at the ferromagnetic to paramagnetic phase transition. Their position agrees quantitatively with experiment. Additionally, we predict that the metamagnetic CEP can be traced down to zero temperature and becomes quantum critical point by a small decrease of both the total electron concentration and the external pressure. The system properties are then determined by the quantum critical fluctuations appearing near the instability point of the Fermi surface topology.Comment: 4 pages, 4 figures, PACS number: 71.27.+a, 75.30.Kz, 71.10.-

The Use of Geographical Information Systems in the Urban Communes of Łódź Metropolitan Area

The article presents the results of pilot studies carried out in the cities of Łódź Metropolitan Area. The study concerned the use of geographical information system by the employees of offices of these cities. The interest in the subject of GIS in Polish urban communes results from the assumptions of the EU INSPIRE Directive and the necessity of its implementation in the basic units of territorial division of Poland. The aim of the research was the analysis of the impact of GIS on the sphere of the public participation in the process of local management and the possible use of GIS in the decision making in communes. Research showed what kind of software was used in analyzed communes