Physics – High Energy Physics – High Energy Physics - Theory
Scientific paper
2011-10-20
Physics
High Energy Physics
High Energy Physics - Theory
44 pages, 3 figures, longer version of the abstract in the body of the paper; v2 some clarifications and refinements
Scientific paper
Quantum mechanics introduces the concept of probability at the fundamental level, yielding the measurement problem. On the other hand, recent progress in cosmology has led to the "multiverse" picture, in which our observed universe is only one of the many, bringing an apparent arbitrariness in defining probabilities, called the measure problem. In this paper, we discuss how these two problems are intimately related with each other, developing a complete picture for quantum measurement and cosmological histories in the quantum mechanical universe. On one hand, quantum mechanics eliminates the arbitrariness of defining probabilities in the multiverse, as discussed in arXiv:1104.2324. On the other hand, the multiverse allows for understanding why we observe an ordered world obeying consistent laws of physics, by providing an infinite-dimensional Hilbert space. This results in the irreversibility of quantum measurement, despite the fact that the evolution of the multiverse state is unitary. In order to describe the cosmological dynamics correctly, we need to identify the structure of the Hilbert space for a system with gravity. We argue that in order to keep spacetime locality, the Hilbert space for dynamical spacetime must be defined only in restricted spacetime regions: in and on the (stretched) apparent horizon as viewed from a fixed reference frame. This requirement arises from eliminating all the redundancies and overcountings in a general relativistic, global spacetime description of nature. It is responsible for horizon complementarity as well as the "observer dependence" of horizons/spacetime---these phenomena arise to represent changes of the reference frame in the relevant Hilbert space. This can be viewed as an extension of the Poincare transformation in the quantum gravitational context, as the Lorentz transformation is viewed as an extension of the Galilean transformation.
No associations
LandOfFree
Quantum Mechanics, Spacetime Locality, and Gravity does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Quantum Mechanics, Spacetime Locality, and Gravity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Quantum Mechanics, Spacetime Locality, and Gravity will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-84428