Joint Condensed Matter and Gravitation Theory Seminar

Thursday, October 12, 2000, 2 p.m.
Plant Sciences Building, Room 1130

Sonic Pulses from Crossed Vortices in Liquid 4He: A Simulation of High-Energy Radiation from Crossed Cosmic Strings

Richard Ferrell

(Department of Physics, University of Maryland)

Abstract:  The crossing and recombination of a pair of cosmic strings provides a plausible explanation for the extremely high amount of energy that is observed in gamma ray bursts.  Cosmic strings are hypothesized remnants that are expected inevitably to be left over from the phase transition that must have taken place in the early universe.  We are proposing, as an analogue that can be studied in the laboratory, an experiment to detect the crossing and recombination of a pair of vortices in superfluid 4He.  Like the cosmic strings, these are topological singularities with surplus trapped energy stored in their cores.  Although nominally metastable, such a singularity is an excited state of the system that has robust stability until it is triggered to release its energy of excitation by an the encounter with a second singularity.  These energy bursts will generate pressure pulses detectable by suitable instrumentation.  A simple model yield a characteristic time signature for the sonic pulses that should enable their unambiguous identification.

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