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Full-Text Articles in Physical Sciences and Mathematics

Quantization Of Maximally Charged Slowly Moving Black Holes, George Siopsis May 2001

Quantization Of Maximally Charged Slowly Moving Black Holes, George Siopsis

George Siopsis

We discuss the quantization of a system of slowly moving extreme Reissner-Nordström black holes. In the near-horizon limit, this system has been shown to possess an SL(2,R) conformal symmetry. However, the Hamiltonian appears to have no well-defined ground state. This problem can be circumvented by a redefinition of the Hamiltonian due to de Alfaro, Fubini, and Furlan (DFF). We apply the Faddeev-Popov quantization procedure to show that the Hamiltonian with no ground state corresponds to a gauge in which there is an obstruction at the singularities of moduli space requiring a modification of the quantization rules. The …


Simulation Of Inviscid Multi-Species Plasma Flow, Alexandre Martin, Marcelo Reggio, Jean-Yves Trépanier May 2001

Simulation Of Inviscid Multi-Species Plasma Flow, Alexandre Martin, Marcelo Reggio, Jean-Yves Trépanier

Alexandre Martin

A multi-species solver for plasma at thermodynamical equilibrium is developed. A numerical scheme, based on Roe's, is implemented with some modification regarding the average quantities. A perfect gas treatment is carried out for validations, and a quasi-real gas treatment is also presented. The latter takes into account the changes in the composition of the gas caused by fluctuations in temperature and density.


Knots And Random Walks In Vibrated Granular Chains, E. Ben-Naim, Z.A. Daya, P. Vorobieff, R.E. Ecke Feb 2001

Knots And Random Walks In Vibrated Granular Chains, E. Ben-Naim, Z.A. Daya, P. Vorobieff, R.E. Ecke

Eli Ben-Naim

We study experimentally statistical properties of the opening times of knots in vertically vibrated granular chains. Our measurements are in good qualitative and quantitative agreement with a theoretical model involving three random walks interacting via hard core exclusion in one spatial dimension. In particular, the knot survival probability follows a universal scaling function which is independent of the chain length, with a corresponding diffusive characteristic time scale. Both the large-exit-time and the small-exit-time tails of the distribution are suppressed exponentially, and the corresponding decay coefficients are in excellent agreement with the theoretical values.


N-Methyl-D-Aspartate Channel And Consciousness: From Signal Coincidence Detection To Quantum Computing, Armando F. Rocha, Alfredo Pereira Jr Jan 2001

N-Methyl-D-Aspartate Channel And Consciousness: From Signal Coincidence Detection To Quantum Computing, Armando F. Rocha, Alfredo Pereira Jr

Armando F Rocha

Research on Blindsight, Neglect/Extinction and Phantom limb syndromes, as well as electrical measurements of mammalian brain activity, have suggested the dependence of vivid perception on both incoming sensory information at primary sensory cortex and reentrant information from associative cortex. Coherence between incoming and reentrant signals seems to be a necessary condition for (conscious) perception. General reticular activating system and local electrical synchronization are some of the tools used by the brain to establish coarse coherence at the sensory cortex, upon which biochemical processes are coordinated. Besides electrical synchrony and chemical modulation at the synapse, a central mechanism supporting such a …


The Age Of Entanglement Jan 2001

The Age Of Entanglement

David D Nolte

Quantum mechanics is a venerable field of study. The year 2000 marked the 100th anniversary of theoriginal quantum hypothesis proposed by Max Planck in November of 1900. Few current fields in physicsor engineering are as old as quantum mechanics. It predates relativity, both special and general. It predatesnuclear and particle physics. Quantum mechanics even predates universal acceptance of the molecularhypothesis, that is, that all matter is made up of individual molecules in thermal motion. It may be hard tobelieve, but this happened only after Einstein's paper on Brownian motion was published in his miracleyear 1905.