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Holographic spacetime model of inflation and its predictions for the CMB primordial spectra

Sidan A* and Tom Banks†

  • *Contact author: sidan.aa@rutgers.edu
  • †Contact author: tibanks@ucsc.edu
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Phys. Rev. D 112, 023516 – Published 8 July, 2025

DOI: https://doi.org/10.1103/xts8-ggmg

Abstract

In 1998 Carlip [Nucl. Phys. B, Proc. Suppl. 88, 10 (2000)] and Solodukhin [Phys. Lett. B 454, 213 (1999)] independently conjectured the equality between fluctuations in the modular Hamiltonian of black holes and its expectation value. Banks and Zurek’s 2021 work [T. Banks and K. M. Zurek, Phys. Rev. D 104, 126026 (2021)] generalized this observation to any causal diamonds. We use this observation to calculate the precise normalization of primordial scalar and tensor power spectra in the holographic space-time model of inflation. In previous work [T. Banks and W. Fischler, arXiv:1501.01686.] Banks and Fischler outlined the general calculation of inflationary power spectra in this model, which we review here. Its conceptual basis is radically different from field theoretic inflation and it has no trans-Planckian problem, but its predictions for power spectra will be shown to fit extant data equally well, and the tensor-to-scalar ratio agrees with experimental observations.

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Phys. Rev. D 112, 023516– Published 8 July, 2025
  • Received 11 March 2025
  • Accepted 19 June 2025
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