PIRSA:17100086

Classical branches and entanglement structure in the wavefunction of cosmological fluctuations

APA

Nelson, E. (2017). Classical branches and entanglement structure in the wavefunction of cosmological fluctuations. Perimeter Institute for Theoretical Physics. https://pirsa.org/17100086

MLA

Nelson, Elliot. Classical branches and entanglement structure in the wavefunction of cosmological fluctuations. Perimeter Institute for Theoretical Physics, Oct. 31, 2017, https://pirsa.org/17100086

BibTex

          @misc{ scivideos_PIRSA:17100086,
            doi = {10.48660/17100086},
            url = {https://pirsa.org/17100086},
            author = {Nelson, Elliot},
            keywords = {Cosmology},
            language = {en},
            title = {Classical branches and entanglement structure in the wavefunction of cosmological fluctuations},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2017},
            month = {oct},
            note = {PIRSA:17100086 see, \url{https://scivideos.org/index.php/pirsa/17100086}}
          }
          

Elliot Nelson IBM (United States)

Talk numberPIRSA:17100086
Source RepositoryPIRSA
Talk Type Scientific Series
Subject

Abstract

The emergence of classical behavior from an out-of-equilibrium quantum wavefunction is determined by its entanglement structure, in the form of redundant information shared between many local subsystems. We show how this structure can be generated via cosmological dynamics from the vacuum state of a massless field, causing the wavefunction to branch into classical field configurations.  An accelerating epoch first excites the vacuum into a superposition of classical fields alongside a highly sensitive bath of super-horizon particles. Gravitational interactions allow these quanta to collect information about the long-wavelength field. During a subsequent decelerating epoch, this information propagates spatially, creating long-range redundant correlations in the wavefunction. The resulting classical observables (field configurations), preferred basis for decoherence, and system/environment decomposition emerge from the translation invariant wavefunction and Hamiltonian, rather than being fixed by hand. We discuss the implications for the classicality of cosmological perturbations.