A Unique Theory of Gravity and Matter

The author has previously suggested that the ground state for 4-dimensional quantum gravity can be represented as a condensation of non-linear gravitons connected by Dirac strings. In this note we suggest that the low-lying excitations of this state can be described by a quasi-topological action corresponding to a trilinear coupling of solitonic 8-branes and 7-branes. It is shown that when the 7-brane excitations are neglected, the effective action can be interpreted as a theory of conformal gravity in four dimensions. This suggests that ordinary gravity as well as supersymmetric matter and phenomenological gauge symmetries arise from the spontaneous breaking of topological invariance.Comment: PostScript, 12 page

Quantum Criticality and the Alpha/Delta Puzzle

In this paper we suggest a novel explanation for the alpha-delta transition in plutonium based on an analogy between the evolution of the actinide ground state as a function of spin orbit coupling and the behaviour of thin film superconductors in a magnetic field. The key point is that in metals with a low carrier density spin-orbit interactions give rise to low energy monopole-like solitons with quantized spin currents, which play much the same role as Abrikosov vortices in thin film superconductors. In alpha-plutonium these solitons form an ordered solid, while in impurity stabilized delta-plutonium they form a pair condensate.Comment: 7 pages, 1 figur

The Monster Sporadic Group and a Theory Underlying Superstring Models

The pattern of duality symmetries acting on the states of compactified superstring models reinforces an earlier suggestion that the Monster sporadic group is a hidden symmetry for superstring models. This in turn points to a supersymmetric theory of self-dual and anti-self-dual K3 manifolds joined by Dirac strings and evolving in a 13 dimensional spacetime as the fundamental theory. In addition to the usual graviton and dilaton this theory contains matter-like degrees of freedom resembling the massless states of the heterotic string, thus providing a completely geometric interpretation for ordinary matter.Comment: 14 pages; PostScrip

Sentient Networks

In this paper we consider the question whether a distributed network of sensors and data processors can form "perceptions" based on the sensory data. Because sensory data can have exponentially many explanations, the use of a central data processor to analyze the outputs from a large ensemble of sensors will in general introduce unacceptable latencies for responding to dangerous situations. A better idea is to use a distributed "Helmholtz machine" architecture in which the collective state of the network as a whole provides an explanation for the sensory data.Comment: PostScript, 14 page