Baby universes in 2d and 4d theories of quantum gravity
arXiv:2210.05134 · doi:10.1007/JHEP12(2022)100
Abstract
The validity of the Coleman mechanism, which automatically tunes the fundamental constants, is examined in two-dimensional and four-dimensional quantum gravity theories. First, we consider two-dimensional Euclidean quantum gravity on orientable closed manifolds coupled to conformal matter of central charge . The proper time Hamiltonian of this system is known to be written as a field theory of noncritical strings, which can also be viewed as a third quantization in two dimensions. By directly counting the number of random surfaces with various topologies, we find that the contribution of the baby universes is too small to realize the Coleman mechanism. Next, we consider four-dimensional Lorentzian gravity. Based on the difference between the creation of the mother universe from nothing and the annihilation of the mother universe into nothing, we introduce a non-Hermitian effective Hamiltonian for the multiverse. We show that Coleman's idea is satisfied in this model and that the cosmological constant is tuned to be nearly zero. Potential implications for phenomenology are also discussed.
arXiv comment23 pages, 4 figures; version to appear in JHEP (v2)
References in corpus (30)
- 2D Gravity and Random Matrices
- Replica Wormholes and the Entropy of Hawking Radiation
- The entropy of bulk quantum fields and the entanglement wedge of an evaporating black hole
- The entropy of Hawking radiation
- Liouville Field Theory -- A decade after the revolution
- Transfer Matrix Formalism for Two-Dimensional Quantum Gravity and Fractal Structures of Space-time
- Higgs inflation from Standard Model criticality
- Euclidean wormholes, baby universes, and their impact on particle physics and cosmology
- Liouville quantum gravity -- holography, JT and matrices
- Defects in Jackiw-Teitelboim Quantum Gravity
- String Field Theory of Noncritical Strings
- String Field Theory of Noncritical Strings
- Minimal Higgs inflation
- Dilaton-gravity, deformations of the minimal string, and matrix models
- Touching Random Surfaces and Liouville Gravity
- Solving the Naturalness Problem by Baby Universes in the Lorentzian Multiverse
- Multi-spin systems on a randomly triangulated surface
- Evidence of the Big Fix
- Scaling Functions for Baby Universes in Two-Dimensional Quantum Gravity
- FZZT branes in JT gravity and topological gravity
- String Field Theory in the Temporal Gauge
- Liouville theory and Matrix models: A Wheeler DeWitt perspective
- Asymptotically Vanishing Cosmological Constant in the Multiverse
- Two-Dimensional Quantum Gravity in Temporal Gauge
- Generalized multicritical one-matrix models
- Correlation Functions in Matrix Models Modified by Wormhole Terms
- Weak Scale From the Maximum Entropy Principle
- Natural solution to the naturalness problem -- Universe does fine-tuning
- Wormholes, a fluctuating cosmological constant and the Coleman mechanism
- Replica Wormholes from Liouville Theory