Cornell physicist Brian Greene recently made a discovery that takes us one step closer to the tantalizing possibility that string theory can unify all of theoretical physics. Working with a visiting colleague, mathematician David Morrison of Duke University, and Andrew Strominger of the University of California at Santa Barbara, Greene found that tiny black holes can be transformed mathematically into infinitesimal vibrating loops of energy-superstrings. According to string theory, these loops also lie at the core of elementary particles such as electrons and quarks. In fact, it appears that all three (superstrings, black holes, and elementary particles) may be expressions of the same thing--of everything.
Greene and Morrison were inspired by an on-line preprint of physicist Andrew Strominger at the University of California, Santa Barbara. In it Strominger showed how certain black holes could be used to resolve a problem spot in string theory concerning a class of spacetime singularities, points at which the smooth surface describing the four dimensions of spacetime is broken. When he included minute, charged black holes as possible outcomes of the string theory model, the singularities disappeared. On reading this work, Greene and Morrison immediately contacted Strominger.
Within days, the three had completed a striking generalization of Strominger's work that allows the fabric of spacetime to tear apart in a physically sensible manner. This is a radical modification of Einstein's original conception, which requires spacetime to remain a smooth and continuous surface.
Greene presents this breakthrough in an illustrated talk. To explain the abstract concepts, he has worked with Cornell Theory Center (CTC) visualization producer Wayne Lytle to create animated sequences presenting the fundamentals of string theory and the specifics of the contribution he and his colleagues have made to it. Lytle's visualizations represent dynamic shapes changing topologies based on parametric equations supplied by Greene. They were created within the Visual Programming Language for Animation (VPLA) computing environment recently developed by Lytle and were rendered in parallel on CTC's SGI ONYX.
Greene, Morrison, and Strominger have found that string theory goes beyond the mathematics of topology and the physics of general relativity. It allows the fabric of spacetime to tear in a manner analogous to the transformation of the sphere into a torus. The point at which the sphere tears is a critical transition. This is the moment when the black hole becomes infinitesimally small and has no mass.
The transformation shows that, rather than disappearing, the black hole reemerges in another form, as an elementary particle. Thus they show that space can "rip" apart and subsequently "reconnect," thereby changing its basic structure (topology), without breaking the rules of string theory.
Greene and his colleagues have shown that black holes and elementary particles are "two phases" of the same basic substance with a relationship similar to that of ice and water. According to Greene, "Research in string theory, the most promising candidate for a unified description of nature's forces, has revealed that the fabric of spacetime can evolve in far more dramatic ways than allowed for in more traditional theories such as general relativity."
String Theory
Dancing Dimensions
Visual Programming