Chris Dewdney

Spin and non-locality in quantum mechanics

Spin superposition in neutron interferometry, spin measurement, and non–local Einstein-Podolsky-Rosen spin correlations can be understood in terms of well–defined individual particle trajectories with continuously variable spin vectors.

Bohm particles and their detection in the light of neutron interferometry

Properties sometimes attributed to the “particle” aspect of a neutron, e.g., mass and magnetic moment, cannot straightforwardly be regarded in the Bohm interpretation of quantum mechanics as localized at the hypothetical position of the particle. This is shown by examining a series of effects in neutron interferometry. A related thought-experiment also provides a variation of a recent demonstration that which-way detectors can appear to behave anomolously in the Bohm theory.

How late measurements of quantum trajectories can fool a detector

Abstract We show how, in the Bohm model, the significance to be attached to the readings of a detector depends on the context in which it is used.

A non-local, Lorentz-invariant, hidden-variable interpretation of relativistic quantum mechanics based on particle trajectories

We demonstrate how to construct a Lorentz-invariant, hidden-variable interpretation of relativistic quantum mechanics based on particle trajectories. The covariant theory that we propose employs a multi-time formalism and a Lorentz-invariant rule for the coordination of the spacetime points on the individual particle trajectories. In this way we show that there is no contradiction between non-locality and Lorentz-invariance in quantum mechanics. The approach is illustrated for relativistic bosons, using a simple model to discuss the individual non-locally correlated particle motion which ensues when the wavefunction is entangled. A simple example of measurement is described.

Measurement, decoherence and chaos in quantum pinball

Abstract The effect of introducing measuring devices in a “quantum pinball” system is shown to lead to a chaotic evolution for the particle position as defined in Bohms approach to quantum mechanics.

A quantum potential approach to spin superposition in neutron interferometry

Abstract The causal interpretation of the Pauli equation is shown to provide an understanding of spin superposition in neutron interferometry in terms of well-defined individual particle trajectories with continuously variable spin vectors.

Wave-particle dualism and the interpretation of quantum mechanics

The realist interpretations of quantum theory, proposed by de Broglie and by Bohm, are re-examined and their differences, especially concerning many-particle systems and the relativistic regime, are explored. The impact of the recently proposed experiments of Vigier et al. and of Ghose et al. on the debate about the interpretation of quantum mechanics is discussed. An indication of how de Broglie and Bohm would account for these experimental results is given.

Large Coastal Landslides and Tsunami Hazard in the Caribbean

With nine volcanic peaks in a 750-square-kilometer area, Dominica, in the Lesser Antilles volcanic arc (Figure 1), has one of the highest concentrations of potentially active volcanoes in the world [Lindsay et al., 2005]. Dominica is very hilly, and there have been numerous landslides, particularly on the islands wetter eastern and northern coasts. Lindsay et al. [2005] consider the likelihood of gravitational collapses on the flanks of Dominicas volcanoes to be “low but not negligible.” However, many factors make Dominica particularly prone to large landslides (>1 million tons): (1) extensive zones of weakened rock, due to hydrothermal alteration and/or intense tropical weathering; (2) oversteepened slopes associated with tectonic uplift and erosion of volcanic edifice foot slopes; (3) large amounts of rainfall on the volcanic uplands, especially during the hurricane season (June–October), with annual averages of up to approximately 6000 millimeters; and (4) occasional severe seismic activity, e.g., a magnitude 7.3 earthquake on 29 November 2007, with its epicenter between Dominica and Martinique, and another of magnitude 6.2 on 21 November 2004, with its epicenter between Dominica and Guadeloupe.

A relativistically covariant version of Bohm's quantum field theory for the scalar field

We give a relativistically covariant, wave-functional formulation of Bohms quantum field theory for the scalar field based on a general foliation of spacetime by space-like hypersurfaces. The wave functional, which guides the evolution of the field, is spacetime-foliation independent but the field itself is not. Hence, in order to have a theory in which the field may be considered a beable, some extra rule must be given to determine the foliation. We suggest one such rule based on the eigenvectors of the energy–momentum tensor of the field itself.

Relativistically invariant extension of the de Broglie–Bohm theory of quantum mechanics

We show that quantum mechanics can be given a Lorentz-invariant realistic interpretation by applying our recently proposed relativistic extension of the de Broglie–Bohm theory to deduce non-locally correlated, Lorentz-invariant individual particle motions for the Einstein–Podolsky–Rosen experiment and the double-interferometer experiment proposed by Horne, Shimony and Zeilinger.