Hartle–Hawking state
The Hartle–Hawking state, also known as the no-boundary wave function is a proposal in
.According to the Hartle–Hawking proposal, the universe has no origin as we would understand it: before the Big Bang, which happened about 13.8 billion years ago, the universe was a singularity in both space and time. Hartle and Hawking suggest that if we could travel backwards in time towards the beginning of the universe, we would note that quite near what might have been the beginning, time gives way to space so that there is only space and no time.[4]
Technical explanation
More precisely, the Hartle-Hawking state is a hypothetical
wave function of the universe
.
It is a
Planck time.[5]
Such a wave function of the universe can be shown to satisfy, approximately, the Wheeler–DeWitt equation.
See also
- Imaginary time
- Multiple histories
- Signature change
References
- S2CID 121947045.
- .
- ISSN 0034-6861.
- ^ Hawking, Stephen. "The Beginning of Time". Archived from the original on 6 October 2014. Retrieved 10 March 2014.
- ^ John D. Barrow, The Origin of the universe: To the Edge of Space and Time, Basic Books, 1997.