Hydrodynamic Detonation Instability in Electroweak and QCD Phase Transitions

The hydrodynamic stability of deflagration and detonation bubbles for a first order electroweak and QCD phase transition has been discussed recently with the suggestion that detonations are stable. We examine here the case of a detonation more carefully. We find that in front of the bubble wall perturbations do not grow with time, but behind the wall modes exist which grow exponentially. We briefly discuss the possible meaning of this instability.Comment: 12 pages, 3 figures available on request, Latex, FERMILAB--PUB--93/098--

Uniform Shock Waves in Disordered Granular Matter

The confining pressure $P$ is perhaps the most important parameter controlling the properties of granular matter. Strongly compressed granular media are, in many respects, simple solids in which elastic perturbations travel as ordinary phonons. However, the speed of sound in granular aggregates continuously decreases as the confining pressure decreases, completely vanishing at the jamming-unjamming transition. This anomalous behavior suggests that the transport of energy at low pressures should not be dominated by phonons. In this work we use simulations and theory to show how the response of granular systems becomes increasingly nonlinear as pressure decreases. In the low pressure regime the elastic energy is found to be mainly transported through nonlinear waves and shocks. We numerically characterize the propagation speed, shape, and stability of these shocks, and model the dependence of the shock speed on pressure and impact intensity by a simple analytical approach.Comment: 12 pages, 11 figure

Anisotropy of polarizability of the silatranes

1. Polarizability parameters have been determined for the Si-C and Si-O bonds. The Si-O bond of the siloxanes does not show axial symmetry. 2. The axes of the molecular polarizability ellipsoid for 1-methylsilatrane have been determined. 3. The transannular N → Si bond shows a pronounced anisotropy of polarizability in the silatranes. © 1977 Plenum Publishing Corporation

Anisotropy of polarizability of the silatranes

1. Polarizability parameters have been determined for the Si-C and Si-O bonds. The Si-O bond of the siloxanes does not show axial symmetry. 2. The axes of the molecular polarizability ellipsoid for 1-methylsilatrane have been determined. 3. The transannular N → Si bond shows a pronounced anisotropy of polarizability in the silatranes. © 1977 Plenum Publishing Corporation

Anisotropy of polarizability of the silatranes

1. Polarizability parameters have been determined for the Si-C and Si-O bonds. The Si-O bond of the siloxanes does not show axial symmetry. 2. The axes of the molecular polarizability ellipsoid for 1-methylsilatrane have been determined. 3. The transannular N → Si bond shows a pronounced anisotropy of polarizability in the silatranes. © 1977 Plenum Publishing Corporation

Anisotropy of polarizability of the silatranes

1. Polarizability parameters have been determined for the Si-C and Si-O bonds. The Si-O bond of the siloxanes does not show axial symmetry. 2. The axes of the molecular polarizability ellipsoid for 1-methylsilatrane have been determined. 3. The transannular N → Si bond shows a pronounced anisotropy of polarizability in the silatranes. © 1977 Plenum Publishing Corporation