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Non-local quantum effects in cosmology 1: Quantum memory, non-local FLRW equations and singularity avoidance
Physical Review D (2014)
  • John Donoghue
  • Basem K Mahmoud El-Menoufi
Abstract
We discuss cosmological effects of the quantum loops of massless particles, which lead to temporal
non-localities in the equations of motion governing the scale factor a(t). For the effects discussed
here, loops cause the evolution of a(t) to depend on the memory of the curvature in the past with
a weight that scales initially as 1/(t − t′). As one of our primary examples we discuss the situation
with a large number of light particles, such that these effects occur in a region where gravity may
still be treated classically. However, we also describe the effect of quantum graviton loops and the
full set of Standard Model particles. We show that these effects decrease with time in an expanding
phase, leading to classical behavior at late time. In a contracting phase, within our approximations
the quantum results can lead to a bounce-like behavior at scales below the Planck mass, avoiding
the singularities required classically by the Hawking-Penrose theorems. For conformally invariant
fields, such as the Standard Model with a conformally coupled Higgs, this result is purely non-local
and parameter independent.
Disciplines
Publication Date
2014
DOI
10.1103/PhysRevD.89.104062
Citation Information
John Donoghue and Basem K Mahmoud El-Menoufi. "Non-local quantum effects in cosmology 1: Quantum memory, non-local FLRW equations and singularity avoidance" Physical Review D Vol. 89 Iss. 1004062 (2014)
Available at: http://works.bepress.com/john_donoghue/167/