English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

A non-perturbative study on the quantum fluctuations of light ray propagationthrough a quantum region of spacetime is long overdue. Within the theory ofLorentzian simplicial quantum gravity, we compute the probabilities for a testlight ray to land at different locations after travelling through asymmetry-reduced box region in 2,3 and 4 spacetime dimensions. It is found thatfor fixed boundary conditions, light ray fluctuations are generically largewhen all coupling constants are relatively small in absolute value. For fixedcoupling constants, as the boundary size is decreased light ray fluctuationsfirst increase and then decrease in a 2D theory with the cosmological constant,Einstein-Hilbert and R-squared terms. While in 3D and 4D theories with thecosmological constant and Einstein-Hilbert terms, as the boundary size isdecreased light ray fluctuations just increase. Incidentally, when studying 2Dquantum gravity we show that the global time-space duality with thecosmological constant and Einstein-Hilbert terms noted previously also holdswhen arbitrary even powers of the Ricci scalar are added. We close bydiscussing how light ray fluctuations can be used in obtaining the continuumlimit of non-perturbative Lorentzian quantum gravity.

Light ray fluctuations in simplicial quantum gravity