How do late-time photons "record" primordial curvature perturbations?
gr-qc, astro-ph.CO, hep-th, quant-ph
Submitted: 2026-10-15
Updated: 2026-10-15
Comments: 7 pages, 2 figures
License: http://creativecommons.org/licenses/by/4.0/
The gist: Inflationary cosmology faces a fundamental gap between primordial quantum fluctuations and the classical cosmic history inferred from observations.
Abstract
Inflationary cosmology faces a fundamental gap between primordial quantum fluctuations and the classical cosmic history inferred from observations. Although the primordial quantum state is a superposition of field configurations, standard cosmology assumes one definite realization of curvature perturbations and uses classical perturbation theory to describe the resulting gravitational potentials, CMB anisotropies, and large-scale structure. Squeezing and decoherence of primordial fluctuations alone do not explain why this one-realization description is physically meaningful. We address this issue through Cosmological Classical Branches (CCBs), using the quantum-information-theoretic notion of physical records. In CCBs, distinct late-time matter components carry compatible records of the same primordial configuration. A record in one component makes that configuration readable, while a disjoint compatible record suppresses interference accessible to operations on the first. Each branch thus admits a common c-number primordial label at finite resolution, while the global quantum superposition persists. This Letter summarizes the framework developed in Ref..
Related papers
- Listening to the Horizon: Probing Near-Horizon Reflectivity with GW250114
- A Pairwise Surrogate for Gravitational-Wave Spectra from Highly Relativistic Vacuum Bubble Collisions
- Tests of General Relativity with Einstein Telescope
- A weakly modelled view of the joint compact-binary mass plane: population structure and spectral-siren cosmology
- Unitary quantum matter-bounce in a universe with a positive cosmological constant
- Nonreciprocal black holes with primary hair in beyond Horndeski gravity: Exact solutions and stability