Quantum nature of the big bang

Abhay Ashtekar, Tomasz Pawlowski, Parampreet Singh

Research output: Contribution to journalArticlepeer-review

526 Scopus citations


Some long-standing issues concerning the quantum nature of the big bang are resolved in the context of homogeneous isotropic models with a scalar field. Specifically, the known results on the resolution of the big-bang singularity in loop quantum cosmology are significantly extended as follows: (i) the scalar field is shown to serve as an internal clock, thereby providing a detailed realization of the "emergent time" idea; (ii) the physical Hilbert space, Dirac observables, and semiclassical states are constructed rigorously; (iii) the Hamiltonian constraint is solved numerically to show that the big bang is replaced by a big bounce. Thanks to the nonperturbative, background independent methods, unlike in other approaches the quantum evolution is deterministic across the deep Planck regime.

Original languageEnglish (US)
Article number141301
JournalPhysical review letters
Issue number14
StatePublished - 2006

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)


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