Hartle–Hawking no-boundary proposal
E518521
The Hartle–Hawking no-boundary proposal is a quantum cosmological model suggesting that the universe is finite but without an initial temporal boundary, replacing the classical Big Bang singularity with a smooth, boundaryless beginning described by quantum gravity.
Observed surface forms (1)
| Surface form | Occurrences |
|---|---|
| Hartle–Hawking state | 1 |
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
cosmological model
ⓘ
quantum cosmology proposal ⓘ theoretical physics concept ⓘ |
| addresses |
arrow of time problem
ⓘ
cosmological fine-tuning ⓘ initial conditions of the universe ⓘ |
| avoids | initial cosmological singularity ⓘ |
| boundaryCondition | no boundary in the Euclidean past ⓘ |
| comparedWith | Vilenkin tunneling proposal NERFINISHED ⓘ |
| contrastsWith | classical Big Bang singularity ⓘ |
| coreIdea |
space and time emerge from a Euclidean quantum regime
ⓘ
the classical Big Bang singularity is replaced by a smooth beginning ⓘ the early universe is described by quantum gravity ⓘ the universe has no initial boundary in time ⓘ the universe is finite but without temporal boundary ⓘ |
| criticizedFor |
interpretational issues about time
ⓘ
mathematical ambiguities in Euclidean path integrals ⓘ measure problems in quantum cosmology ⓘ |
| describes |
early universe
ⓘ
origin of the universe ⓘ quantum state of the universe ⓘ |
| field |
cosmology
ⓘ
quantum cosmology ⓘ theoretical physics ⓘ |
| influenced |
modern discussions of the wave function of the universe
ⓘ
subsequent work in quantum gravity ⓘ |
| involves |
compact four-dimensional geometries
ⓘ
saddle-point approximation ⓘ semiclassical approximation ⓘ |
| mathematicalFormulation | path integral over compact Euclidean four-geometries ⓘ |
| predicts |
a specific wave function for the universe
ⓘ
nearly homogeneous and isotropic early universe ⓘ probability distribution over possible universes ⓘ |
| proposedBy |
James Hartle
NERFINISHED
ⓘ
Stephen Hawking NERFINISHED ⓘ |
| publication | “Wave Function of the Universe” NERFINISHED ⓘ |
| publicationYear | 1983 ⓘ |
| publishedIn | Physical Review D NERFINISHED ⓘ |
| relatedTo |
inflationary cosmology
ⓘ
loop quantum cosmology NERFINISHED ⓘ multiverse models ⓘ string cosmology ⓘ |
| timeBehavior | time behaves like a spatial dimension near the beginning ⓘ |
| usesConcept |
Euclidean quantum gravity
NERFINISHED
ⓘ
Wheeler–DeWitt equation NERFINISHED ⓘ path integral formulation ⓘ wave function of the universe ⓘ |
Referenced by (4)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
Hartle–Hawking state