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The effectiveness of probabilistic structural testing depends on the characteristics of the probability distribution from which test inputs are sampled at random. Metaheuristic search has been shown to be a practical method of optimising the characteristics of such distributions. However, the applicability of the existing search-based algorithm is limited… (More)

- Mark J Hadley
- 1997

For the first time it is shown that the logic of quantum mechanics can be derived from Classical Physics. An orthomodular lattice of propositions , characteristic of quantum logic, is constructed for manifolds in Einstein's theory of general relativity. A particle is modelled by a topo-logically non-trivial 4-manifold with closed timelike curves-a 4-geon,… (More)

- Mark J Hadley
- 2000

It is shown that models of elementary particles in classical general relativity will naturally have the transformation properties of a spinor if the spacetime manifold is not time orientable. From a purely pragmatic interpretation of quantum theory this explains why spinors are needed to represent particles. The models are based entirely on classical… (More)

- Mark J Hadley
- 2000

Contrary to established beliefs, spacetime may not be time-orientable. By considering an experimental test of time orientability it is shown that a failure of time-orientability of a spacetime region would be indistinguishable from a particle antiparticle annihilation event.

- Tammo Diemer, Mark J Hadley
- 1999

A new class of electrically charged wormholes is described in which the outer two sphere is not spanned by a compact coorientable hypersurface. These wormholes can therefore display net electric charge from the source free Maxwell's equation. This extends the work of Sorkin on non-space orientable manifolds, to spacetimes which do not admit a time… (More)

- Mark J. Hadley
- 2013

- Mark J Hadley
- 2008

The practice of setting quantum fields as sources for classical general relativity is examined. Several conceptual problems are identified which invalidate apparently innocuous equations. Alternative ways to links classical general relativity with quantum theory using Bohm's theory are proposed.

- Mark J Hadley
- 2007

Classical particle-like solutions of field equations such as general relativity, could account for dark matter. Such particles would not interact quantum mechanically and would have negligible interactions apart from gravitation. As a relic from the big bang, they would be a candidate for cold dark matter consistent with observations.

- Mark J Hadley
- 2007

Spacetime manifolds that are not time orientable play a key role in a gravitational explanation of quantum theory. Such manifolds allow topology change, but also have fascinating additional properties such as net charge from source-free equations and spin half transformation properties. It is shown how the logical structure of propositions and the… (More)

- Mark J Hadley
- 2006

There is a deep structural link between acausal spacetimes and quantum theory. As a consequence quantum theory may resolve some " paradoxes " of time travel. Conversely, non-time-orientable spacetimes naturally give rise to electric charges and spin half. If an explanation of quantum theory is possible, then general relativity with time travel could be it.