de.mpg.escidoc.pubman.appbase.FacesBean
English
 
Help Guide Disclaimer Contact us Login
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

On the Expansions in Spin Foam Cosmology

MPS-Authors
http://pubman.mpdl.mpg.de/cone/persons/resource/persons45866

Hellmann,  Frank
Quantum Gravity & Unified Theories, AEI-Golm, MPI for Gravitational Physics, Max Planck Society;

Locator
There are no locators available
Fulltext (public)

1105.1334
(Preprint), 171KB

PRD84_103516.pdf
(Any fulltext), 212KB

Supplementary Material (public)
There is no public supplementary material available
Citation

Hellmann, F. (2011). On the Expansions in Spin Foam Cosmology. Physical Review D, 84: 103516. doi:10.1103/PhysRevD.84.103516.


Cite as: http://hdl.handle.net/11858/00-001M-0000-000F-3B77-5
Abstract
We discuss the expansions used in spin foam cosmology. We point out that already at the one vertex level arbitrarily complicated amplitudes contribute, and discuss the geometric asymptotics of the five simplest ones. We discuss what type of consistency conditions would be required to control the expansion. We show that the factorisation of the amplitude originally considered is best interpreted in topological terms. We then consider the next higher term in the graph expansion. We demonstrate the tension between the truncation to small graphs and going to the homogeneous sector, and conclude that it is necessary to truncate the dynamics as well.