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

I argue that the prediction of physical discreteness at the Planck scale inloop gravity is a reasonable conclusion that derives from a sensible ensembleof hypotheses, in spite of some contrary arguments considered in an interestingrecent paper by Dittrich and Thiemann. The counter-example presented byDittrich and Thiemann illustrates a pathology which does not seem to be presentin gravity. I also point out a common confusion between two distinct frameworksfor the interpretation of general-covariant quantum theory, and observe thatwithin one of these, the derivation of physical discreteness is immediate, andnot in contradiction with gauge invariance.

Comment on "Are the spectra of geometrical operators in Loop Quantum Gravity really discrete?" by B. Dittrich and T. Thiemann