Low-Energy Spectral Features in GRBs

I discuss low-energy lines in gamma-ray bursts. The process of deconvolving gamma-ray spectral data and the steps needed to demonstrate the existence of a line are explained. Previous observations and the current status of the analysis of the BATSE data are described.Comment: 10 pages, LaTex using Revtex macro aipbook.sty and psfig. To appear in the Proceedings of the 3rd Huntsville Symposium on Gamma-Ray Bursts, AIP, eds. C. Kouveliotou, M. S. Briggs, G. J. Fishma

Quantum Dynamics Simulation with Classical Oscillators

In a previous paper [J.S.Briggs and A.Eisfeld, Phys.Rev.A 85, 052111] we showed that the time-development of the complex amplitudes of N coupled quantum states can be mapped by the time development of positions and velocities of N coupled classical oscillators. Here we examine to what extent this mapping can be realised to simulate the "quantum" properties of entanglement and qubit manipulation. By working through specific examples, e.g. of quantum gate operation, we seek to illuminate quantum/classical differences which hitherto have been treated more mathematically. In addition we show that important quantum coupled phenomena, such as the Landau-Zener transition and the occurrence of Fano resonances can be simulated by classical oscillators

On the Equivalence of Quantum and Classical Coherence in Electronic Energy Transfer

To investigate the effect of quantum coherence on electronic energy transfer, which is the subject of current interest in photosynthesis, we solve the problem of transport for the simplest model of an aggregate of monomers interacting through dipole-dipole forces using both quantum and classical dynamics. We conclude that for realistic coupling strengths quantum and classical coherent transport are identical. This is demonstrated by numerical calculations for a linear chain and for the photosynthetic Fenna-Matthews-Olson (FMO) comple

Search for Supergalactic Anisotropies in the 3B Catalog

The angular distribution of GRBs is isotropic, while the brightness distribution of bursts shows a reduced number of faint events. These observations favor a cosmological burst origin. If GRBs are indeed at cosmological distances and if they trace luminous matter, we must eventually find an anisotropic distribution of bright bursts. If a significant number of bursts originate at redshifts less than z~1, the concentration of nearby galaxies towards the supergalactic plane is pronounced enough that we could discover the corresponding clustering of burst locations. We used the 3B catalog to search for a pattern visible in supergalactic coordinates. No compelling evidence for anisotropies was found. The absence of anisotropies in SG coordinates implies a minimum sampling distance of 200h^-1 Mpc.Comment: 5 pages, uuencoded postscript, to appear in the Proceedings of the Huntsville Conference on Gamma Ray Burst

Modified hydraulic braking system limits angular deceleration to safe values

Conventional spring actuated, hydraulically released, fail-safe disk braking system is modified to control the angular deceleration of a massive antenna. The hydraulic system provides an immediate preset pressure to the spring-loaded brake shoes and holds it at this value to decelerate the antenna at the desired rate