PIRSA:13110085

A note on emergent classical behavior and approximations to decoherence functionals

Gomes, H. (2013). A note on emergent classical behavior and approximations to decoherence functionals. Perimeter Institute. https://pirsa.org/13110085

Gomes, Henrique. A note on emergent classical behavior and approximations to decoherence functionals. Perimeter Institute, Nov. 05, 2013, https://pirsa.org/13110085 

          @misc{ pirsa_PIRSA:13110085,
            doi = {10.48660/13110085},
            url = {https://pirsa.org/13110085},
            author = {Gomes, Henrique},
            keywords = {Quantum Foundations},
            language = {en},
            title = {A note on emergent classical behavior and approximations to decoherence functionals},
            publisher = {Perimeter Institute},
            year = {2013},
            month = {nov},
            note = {PIRSA:13110085 see, \url{https://pirsa.org}}
          }

Henrique Gomes University of Oxford

Talk numberPIRSA:13110085
DOI10.48660/13110085
Collection
Talk Type Scientific Series
Subject

Abstract

Although it can only be argued to have become consequential in the study of quantum cosmology, the question ``Why do we observe a classical world? " has been one of the biggest preoccupations of quantum foundations. In the consistent histories formalism, the question is shifted to an analysis of the telltale sign of quantum mechanics: superposition of states. In the consistent histories formalism, histories of the system which ``decohere", i.e. fall out of superposition or have negligible interference can be subjected to a notion of classical probability. In this paper we use an extension of Kirchoff's diffraction formula for wave functions on configuration spaces to give a different analysis and an approximation of decoherence. The Kirchoff diffraction formula lies conveniently at the midway between path integrals, wave equations, and classical behavior. By using it, we formulate an approximate dampening of the amplitude of superposition of histories. The dampening acts on each middle element of the fine-grained history {c_\alpha}, and is a function of the angle formed between {c_{n-1},c_n} and {c_n,c_{n+1}}, as classical trajectories in configuration space. As an example we apply the formalism to a modified gravity theory in the ADM gravitational conformal superspace.