The multiparticle space-time algebra (MSTA) is an extension of Dirac theory to a multiparticle setting, which was first studied by Doran, Lasenby and Gull. The geometric interpretation of this algebra, which it inherits from its one-particle factors, possesses a number of physically compelling features, including a simple explanation for the Pauli exclusion principle and other nonlocal effects in quantum physics. Of particular importance here is the fact that a suitable ideal (or quotient) in the MSTA is isomorphic to the 2^N X 2^N complex matrix algebra usually used to describe the states and observables of distinguishable interacting two-state quantum systems. This enables us to 'lift' existing results in quantum information theory regarding entanglement, decoherence and the quantum / classical transition to space-time, where the full power of the MSTA and its geometrical interpretation can be used to obtain new insights into these foundational issues in quantum theory. These insights can immediately be applied to, and any new predictions tested by, such experimental methods as nuclear magnetic resonance, ion cyclotron resonance, and neutron interferometry.

c.doran@mrao.cam.ac.uk