Why are the effective equations of loop quantum cosmology so accurate?

2013/10/31 by Carlo Rovelli, Edward Wilson-Ewing · 3 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Classical mechanics #Cosmology #Cosmology and Gravitation Theories #Homogeneous #Loop quantum cosmology #Loop quantum gravity #Minisuperspace #Noncommutative and Quantum Gravity Theories #Physics #Quantum #Quantum cosmology #Quantum fluctuation #Quantum gravity #Quantum mechanics #Scale (ratio) #Statistical physics #Theoretical physics #gr-qc

paper · pdf · doi:10.1103/physrevd.90.023538

published as Phys.Rev.D90:023538,2014 · 6 pages, v2: Clarifications and references added

openalex publication_date 2014/07/24 · arxiv created 2014/07/25 · arxiv updated 2015/06/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We point out that the relative Heisenberg uncertainty relations vanish for noncompact spaces in homogeneous loop quantum cosmology. As a consequence, for sharply peaked states quantum fluctuations in the scale factor never become important, even near the bounce point. This shows why quantum backreaction effects remain negligible and explains the surprising accuracy of the effective equations in describing the dynamics of sharply peaked wave packets. This also underlines the fact that minisuperspace models---where it is global variables that are quantized---do not capture the local quantum fluctuations of the geometry.

Citations

• Robustness of key features of loop quantum cosmology

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