Cosmological Measures without Volume Weighting
arXiv:0808.0351 · doi:10.1088/1475-7516/2008/10/025
Abstract
Many cosmologists (myself included) have advocated volume weighting for the cosmological measure problem, weighting spatial hypersurfaces by their volume. However, this often leads to the Boltzmann brain problem, that almost all observations would be by momentary Boltzmann brains that arise very briefly as quantum fluctuations in the late universe when it has expanded to a huge size, so that our observations (too ordered for Boltzmann brains) would be highly atypical and unlikely. Here it is suggested that volume weighting may be a mistake. Volume averaging is advocated as an alternative. One consequence may be a loss of the argument that eternal inflation gives a nonzero probability that our universe now has infinite volume.
15 pages, LaTeX, added references for constant-H hypersurfaces and also an idea for minimal-flux hypersurfaces
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Cited by in corpus (6)
- Generation of fluctuations during inflation: comparison of stochastic and field-theoretic approaches
- Properties of the scale factor measure
- The Born Rule Dies
- Possible Anthropic Support for a Decaying Universe: A Cosmic Doomsday Argument
- Horizon Complementarity and Casimir Violations of the Null Energy Condition
- Do Our Observations Depend upon the Quantum State of the Universe?