16,227 research outputs found
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
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