Sudden Transition between Classical and Quantum Decoherence

We study the dynamics of quantum and classical correlations in the presence of nondissipative decoherence. We discover a class of initial states for which the quantum correlations, quantified by the quantum discord, are not destroyed by decoherence for times t < <(t)over bar>. In this initial time interval classical correlations decay. For t > (t) over bar, on the other hand, classical correlations do not change in time and only quantum correlations are lost due to the interaction with the environment. Therefore, at the transition time (t) over bar the open system dynamics exhibits a sudden transition from classical to quantum decoherence regime.

Intensive temperature and quantum correlations for refined quantum measurements

We consider the concept of temperature in a setting beyond the standard thermodynamics prescriptions. Namely, rather than restricting to standard coarse-grained measurements, we consider observers able to master any possible quantum measurement -a scenario that might be relevant at nanoscopic scales. In this setting, we focus on quantum systems of coupled harmonic oscillators and study the question of whether the temperature is an intensive quantity, in the sense that a block of a thermal state can be approximated by an effective thermal state at the same temperature as the whole system. Using the quantum fidelity as figure of merit, we identify instances in which this approximation is not valid, as the block state and the reference thermal state are distinguishable for refined measurements. Actually, there are situations in which this distinguishability even increases with the block size. However, we also show that the two states do become less distinguishable with the block size for coarse-grained measurements -thus recovering the standard picture. We then go further and construct an effective thermal state which provides a good approximation of the block state for any observables and sizes. Finally, we point out the role that entanglement plays in this scenario by showing that, in general, the thermodynamic paradigm of local intensive temperature applies whenever entanglement is not present in the system. Copyright (C) EPLA, 2012

Classical and quantum aspects of multimode parametric interactions

Parametric interactions in nonlinear crystals represent a powerful tool in the optical manipulation of information, both in the classical and the quantum regime. Here, we analyze in detail classical and quantum aspects of three-and five-mode parametric interactions in chi(2) nonlinear crystals. The equations of motion are explicitly derived and then solved within the parametric approximation. We describe several applications, including holography, all-optical gates, generation of entanglement, and telecloning. Experimental results on the photon distributions and correlations of the generated beams are also reported and discussed.

Dipping Wings:for flute (alto fl), clarinet (bass cot), tpt, vla, vcl, perc and live electronics

commissioned by Ballet Rambert for 60th Anniversary season, choreographer Mary Evelyn, designer Liz Emmanuel. World premiere: Theatre Royal York 03/06/86

SIMLA: Simulating particle dynamics in intense laser and other electromagnetic fields via classical and quantum electrodynamics

We present the Fortran program SIMLA, which is designed for the study of charged particle dynamics in laser and other background fields. The dynamics can be determined classically via the Lorentz force and Landau–Lifshitz equations or, alternatively, via the simulation of photon emission events determined by strong-field quantum-electrodynamics amplitudes and implemented using Monte-Carlo routines. Multiple background fields can be included in the simulation and, where applicable, the propagation direction, field type (plane wave, focussed paraxial, constant crossed, or constant magnetic), and time envelope of each can be independently specified.

Liminal Lines:work for euphonium and live electronics

This is the first in series of works that explores the edges of musical styles, in particular the musical language associated with the brass band traditions and the relationship between this performance genre and the work of experimental electronic composition.

Superimposition: A composition for harp, saxophone and live electronics

Superimposition is built on a live-scoring system. Computer animated graphics combined with computer generated algorithms produce the score in real time based on preferences input by the composer. Notably, this system introduces a methodology for eliciting complex and coordinated rhythms from instrumentalists through notation generated in real time. This work also incorporates a system for live electronics and live sampling and processing.

Electrochemical and quantum chemical investigations of the insecticide fipronil.

This work describes an electrochemical and quantum chemical investigation of the fipronil insecticide. Cyclic voltammetry (CV) and square wave voltammetry (SWV) experiments were performed over a graphite-polyurethane (GPU) composite electrode. The fipronil molecule presents an one?electron irreversible oxidation reaction. Profiting the SWV signal a square wave stripping voltammetry (SWSV) procedure to determine the fipronil molecule in a 0.10 mol L-1 Britton-Robinson buffer solution, pH 8.0 was developed with accumulation potential and time of 0.50 V and 120 s, respectively. The limits of detection and quantification were 0.80 and 2.67 ?g L-1, respectively. Recovery tests were performed in three natural waters samples with values ranging from 99.67 to 101.37%. Quantum chemical studies showed that the nitrogen atom of the pyrazole group is the most probable oxidation site of the fipronil molecule.