Some aspects of organic agriculture development in Bosnia and Herzegovina

Numerous authors and documents (IFOAM, OECD) focused social capital as critical for sustainable human and economic development. In this context social benefits that arise from organic farming is one of the factors that balance «competition» between organic and conventional agriculture. The paper presents some of the results of 6-years project on introducing and development of organic agriculture in the West Balkan countries, specified in Bosnia and Herzegovina. The authors discuss possibilities of organic farming as a matrix for overcoming social tensions and interpersonal relations created in war. Experiences from project indicate that systems of norms and standards and networking needed in exchange of experiences asked for collective action. Work in groups, separated by ethnic and social barriers at the beginning of the project, gradually changed to partnership based on individual contribution, regardless the «start positions». The approach: from environment, health and social aspects toward market and economic values, that offer or-ganic agriculture, could be instrumented in this sense, according to the project's results

Classical and Non-Relativistic Limits of a Lorentz-Invariant Bohmian Model for a System of Spinless Particles

A completely Lorentz-invariant Bohmian model has been proposed recently for the case of a system of non-interacting spinless particles, obeying Klein-Gordon equations. It is based on a multi-temporal formalism and on the idea of treating the squared norm of the wave function as a space-time probability density. The particle's configurations evolve in space-time in terms of a parameter {\sigma}, with dimensions of time. In this work this model is further analyzed and extended to the case of an interaction with an external electromagnetic field. The physical meaning of {\sigma} is explored. Two special situations are studied in depth: (1) the classical limit, where the Einsteinian Mechanics of Special Relativity is recovered and the parameter {\sigma} is shown to tend to the particle's proper time; and (2) the non-relativistic limit, where it is obtained a model very similar to the usual non-relativistic Bohmian Mechanics but with the time of the frame of reference replaced by {\sigma} as the dynamical temporal parameter

Feasibility of an Electro-Optic Link for Bondpad-less CMOS Lab-on-Chips

This paper explores the feasibility of developing CMOS-based lab-on-chips to analyse the properties of a fluid, without the need for bond wires. Both inductive and electro-optical schemes are suggested as possible solutions. Specifically, this paper details a novel approach in achieving electro-optical modulation in unmodified, commercially-available CMOS technology. By exploiting the plasma dispersion effect, it is shown how mid-infrared light can be modulated using parasitic structures designed in a CMOS integrated circuit. Both the fundamental theory and practical realisation are supported with measured data from an experimental setup.Accepted versio

Pair density wave instability and Cooper pair insulators in gapped fermion systems

By analyzing simple models of fermions in lattice potentials we argue that the zero-temperature pairing instability of any ideal band-insulator occurs at a finite momentum. The resulting supersolid state is known as "pair density wave". The pairing momentum at the onset of instability is generally incommensurate as a result of phase-space restrictions and relative strengths of interband and intraband pairing. However, commensurate pairing occurs in the strong-coupling limit and becomes a Cooper-channel analogue of the Halperin-Rice exciton condensation instability in indirect bandgap semiconductors. The exceptional sensitivity of incommensurate pairing to quantum fluctuations can lead to a strongly-correlated insulating regime and a non-BCS transition, even in the case of weak coupling as shown by an exact renormalization group analysis.Comment: Proceedings article for SCES 2010. To appear in Journal of Physics: Conference Serie

Bi2Se3 topological insulator quantum wires

We study the effect of 3D topological insulator (TI) contributions to the band structure and wavefunctions of quasi-one-dimensional electron systems (Q1DES). Our model for this system consists of an effective Hamiltonian derived previously in the literature from the crystal symmetries of Bi2Se3. We find that in wires whose face lies in the plane formed by the y and z crystal directions and whose width is around 25 quintuple layers or more, the bands nearest to the gap are non-monotonic; we show that this has implications for the conductance of the wire. In addition, we observed increasing penetration depth of surface states with increasing wavenumber of the propagating mode. We believe these results have qualitative relevance to the family of 3D topological insulators whose crystal structure is characterised by the space group Equation 1, and that the work done here contributes to the wider field of the study of conductance in topological insulators

Engineering Time-Reversal Invariant Topological Insulators With Ultra-Cold Atoms

Topological insulators are a broad class of unconventional materials that are insulating in the interior but conduct along the edges. This edge transport is topologically protected and dissipationless. Until recently, all existing topological insulators, known as quantum Hall states, violated time-reversal symmetry. However, the discovery of the quantum spin Hall effect demonstrated the existence of novel topological states not rooted in time-reversal violations. Here, we lay out an experiment to realize time-reversal topological insulators in ultra-cold atomic gases subjected to synthetic gauge fields in the near-field of an atom-chip. In particular, we introduce a feasible scheme to engineer sharp boundaries where the "edge states" are localized. Besides, this multi-band system has a large parameter space exhibiting a variety of quantum phase transitions between topological and normal insulating phases. Due to their unprecedented controllability, cold-atom systems are ideally suited to realize topological states of matter and drive the development of topological quantum computing.Comment: 11 pages, 6 figure