2007/03/28 by Charis Anastopoulos, C. Anastopoulos, B. L. Hu
Physics and Astronomy · #Noncommutative and Quantum Gravity Theories #Quantum Electrodynamics and Casimir Effect #Quantum Mechanics and Applications #gr-qc
paper · pdf · doi:10.1088/1742-6596/67/1/012012
published as J.Phys.Conf.Ser.67:012012,2007 · 25 pages, proceedings of DICE06 (Piombino)
arxiv created 2007/03/28 · openalex publication_date 2007/05/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
An increasing number of papers have appeared in recent years on decoherence in quantum gravity at the Planck energy. We discuss the meaning of decoherence in quantum gravity starting from the common notion that quantum gravity is a theory for the microscopic structures of spacetime, and invoking some generic features of quantum decoherence from the open systems viewpoint. We dwell on a range of issues bearing on this process including the relation between statistical and quantum, noise from effective field theory, the meaning of stochasticity, the origin of non-unitarity and the nature of nonlocality in this and related contexts. To expound these issues we critique on two representative theories: One claims that decoherence in quantum gravity scale leads to the violation of CPT symmetry at sub-Planckian energy which is used to explain today's particle phenomenology. The other uses this process in place with the Brownian motion model to prove that spacetime foam behaves like a thermal bath. A companion paper will deal with intrinsic and fundamental decoherence which also bear on issues in classical and quantum gravity.