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arXiv · 2510.24953

Midisuperspacetime foam and the cosmological constant

Steven Carlip
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Abstract

Standard quantum field theory arguments predict an enormous cosmological constant. But what would this mean observationally? For a homogeneous universe the answer is clear, but if the universe is inhomogeneous at the Planck scale, the question becomes more subtle: for a large class of initial data, rapidly expanding and contracting regions coexist and give an average expansion near zero. Classically, such data develop singularities, and we need a quantum description of their evolution. I describe results from a spherically symmetric midisuperspace model, in which the wave function can become trapped for long periods in regions in which the average expansion remains small, effectively hiding a large cosmological constant.

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Steven Carlip. 2025-10-28. Midisuperspacetime foam and the cosmological constant. https://arxiv.org/abs/2510.24953

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