String theory predicts an axiverse of ultralight axions whose effects on CMB polarization, matter power spectrum, and black hole superradiance can be probed by future astrophysical experiments.
Quantization of Four-form Fluxes and Dynamical Neutralization of the Cosmological Constant
5 Pith papers cite this work. Polarity classification is still indexing.
5
Pith papers citing it
abstract
A four-form gauge flux makes a variable contribution to the cosmological constant. This has often been assumed to take continuous values, but we argue that it has a generalized Dirac quantization condition. For a single flux the steps are much larger than the observational limit, but we show that with multiple fluxes the allowed values can form a sufficiently dense `discretuum'. Multiple fluxes generally arise in M theory compactifications on manifolds with non-trivial three-cycles. In theories with large extra dimensions a few four-forms suffice; otherwise of order 100 are needed. Starting from generic initial conditions, the repeated nucleation of membranes dynamically generates regions with a cosmological constant in the observational range. Entropy and density perturbations can be produced.
verdicts
UNVERDICTED 5representative citing papers
In a wafer-modified Bousso-Polchinski model, 99.95% of the 532 million Calabi-Yau fourfold configurations in the Schöller-Skarke database allow vacuum energy spacings of 10^{-120} or smaller, with membrane nucleation transitions dominated by giant flux leaps under thin-wall approximations.
Vacuum bubbles carrying quantized monopole flux on their walls collapse to stable particle-like remnants whose mass is fixed by the wall scale and conserved flux.
Kinetic mixing between hidden-sector fluxes and QCD's topological sector shifts the effective theta angle and produces nonzero <G tilde G>.
String theory imposes constraints on dark energy but permits various construction attempts for de Sitter vacua and single-field exponential quintessence models despite obstructions.
citing papers explorer
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String Axiverse
String theory predicts an axiverse of ultralight axions whose effects on CMB polarization, matter power spectrum, and black hole superradiance can be probed by future astrophysical experiments.
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Small Vacuum Energy and Tunneling in a Modified Bousso-Polchinski Model
In a wafer-modified Bousso-Polchinski model, 99.95% of the 532 million Calabi-Yau fourfold configurations in the Schöller-Skarke database allow vacuum energy spacings of 10^{-120} or smaller, with membrane nucleation transitions dominated by giant flux leaps under thin-wall approximations.
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Topolons: Stable Particle-Like Remnants of Collapsed Vacuum Bubbles
Vacuum bubbles carrying quantized monopole flux on their walls collapse to stable particle-like remnants whose mass is fixed by the wall scale and conserved flux.
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Flux Mixing and CP Violation in QCD
Kinetic mixing between hidden-sector fluxes and QCD's topological sector shifts the effective theta angle and produces nonzero <G tilde G>.
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Dark energy from string theory: an introductory review
String theory imposes constraints on dark energy but permits various construction attempts for de Sitter vacua and single-field exponential quintessence models despite obstructions.