Weaving a classical metric with quantum threads

Abhay Ashtekar, Carlo Rovelli, Lee Smolin

Research output: Contribution to journalArticlepeer-review

284 Scopus citations


Results that illuminate the physical interpretation of states of nonperturbative quantum gravity are obtained using the recently introduced loop variables. It is shown that (i) while local operators such as the metric at a point may not be well defined, there do exist nonlocal operators, such as the area of a given two-surface, which can be regulated diffeomorphism invariantly and which are finite without renormalization; (ii) there exist quantum states which approximate a given metric at large scales, but such states exhibit a discrete structure at the Planck scale.

Original languageEnglish (US)
Pages (from-to)237-240
Number of pages4
JournalPhysical review letters
Issue number2
StatePublished - 1992

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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