Abstract

According to the pilot-wave theory of de Broglie and Bohm (a ‘hidden-variables theory’), quantum physics is a special ‘equilibrium’ case of a much wider ‘nonequilibrium’ physics. This wider physics, which may have existed in the early universe, allows for superluminal signalling and violations of the uncertainty principle. Relativity, too, emerges only in the equilibrium state. After a brief account of the search for violations of quantum mechanics in a cosmological context (on the assumption that the universe started out in a state of ‘quantum nonequilibrium’), we address the consequences of this wider physics for quantum information and computation. Standard protocols for quantum key distribution become insecure, but rigorous consequences for computation remain to be worked out.