CFTs Blueshift Tensor Fluctuations Universally

Abstract

The strong constraints of conformal symmetry cause any nearly-conformal sector to blueshift tensor fluctuations in cosmology. Hidden sectors with approximate conformal symmetry, which may be quite large, are a well-motivated extension of physics beyond the Standard Models of particle physics and cosmology. They can therefore lead to a detectable shift in the tensor tilt for next-generation CMB and gravitational wave experiments. We compute the leading-order contribution to the in-in graviton two-point function from virtual loops in such sectors to demonstrate this universal effect. In units where a single conformally-coupled scalar is 1, limits from Stage-IV CMB experiments could bound the size of this extra sector to be smaller than about 10^15. This would be sufficient to rule out N-Naturalness as a complete resolution of the hierarchy problem.

arXiv comment24 pages, 4 figures

References in corpus (42)

• Non-Gaussian features of primordial fluctuations in single field inflationary models
• Planck 2018 results. X. Constraints on inflation
• Heat kernel expansion: user's manual
• Quantum Contributions to Cosmological Correlations
• On Renormalization Group Flows in Four Dimensions
• Implications of Conformal Invariance in Field Theories for General Dimensions
• Twenty Years of the Weyl Anomaly
• The Exact Superconformal R-Symmetry Maximizes a
• Nonperturbative Formulas for Central Functions of Supersymmetric Gauge Theories
• Black Holes and Large N Species Solution to the Hierarchy Problem
• Black Hole Bound on the Number of Species and Quantum Gravity at LHC
• TASI Lectures on Inflation
• Calabi-Yau fourfolds for M- and F-Theory compactifications
• Positivity Constraints on Anomalies in Supersymmetric Gauge Theories
• On Loops in Inflation
• Les Houches Lectures on Constructing String Vacua
• Einstein Gravity from Conformal Gravity
• Sicilian gauge theories and N=1 dualities
• Giant QCD K-factors beyond NLO
• Primordial Gravitational Waves from Axion-Gauge Fields Dynamics
• Nnaturalness
• Planck constraints on the tensor-to-scalar ratio
• A Critique of the Asymptotic Safety Program
• The "in-in" Formalism and Cosmological Perturbations
• A Guide to Designing Future Ground-based CMB Experiments
• Top Down Approach to 6D SCFTs
• Measuring the spectrum of primordial gravitational waves with CMB, PTA and Laser Interferometers
• Inflationary Perturbations in No-Scale Theories
• One-loop gravitational wave spectrum in de Sitter spacetime
• The F-theory geometry with most flux vacua
• Propagating Speed of Primordial Gravitational Waves
• Tensor Non-Gaussianity Search: Current Status and Future Prospects
• Stochastic gravitational-wave background in quantum gravity
• Dynamical RG and Critical Phenomena in de Sitter Space
• WMAP-normalized Inflationary Model Predictions and the Search for Primordial Gravitational Waves with Direct Detection Experiments
• Forecasting sensitivity on tilt of power spectrum of primordial gravitational waves after Planck satellite
• Tensor Bounds on the Hidden Universe
• The Higgs as a Probe of Supersymmetric Extra Sectors
• Kinetic Mixing at Strong Coupling
• IR Divergence in Inflationary Tensor Perturbations from Fermion Loops
• On $i\epsilon$ Prescription in Cosmology
• One-loop corrections to the primordial tensor spectrum from massless isocurvature fields

Cited by in corpus (14)

• Broken blue-tilted inflationary gravitational waves: a joint analysis of NANOGrav 15-year and BICEP/Keck 2018 data
• Inflation, the Hubble Tension and Early Dark Energy: an alternative overview
• Towards a reliable calculation of relic radiation from primordial gravitational waves
• Inflationary Potential as seen from Different Angles: Model Compatibility from Multiple CMB Missions
• Tracking the Multifield Dynamics with Cosmological Data: A Monte Carlo approach
• Swampland Bounds on Dark Sectors
• An Étude on the Regularization and Renormalization of Divergences in Primordial Observables
• Gravitational waves in a cyclic Universe: resilience through cycles and vacuum state
• Multimodality in the Search for New Physics in Pulsar Timing Data and the Case of Kination-amplified Gravitational-wave Background from Inflation
• Strongly Coupled Sectors in Inflation: Gapless Theories and Unparticles
• Strongly Coupled Sectors in Inflation: Gapped Theories of Unparticles
• Dark Walker in the Early Universe: A Strongly Coupled Sector Model
• Primordial Cosmology of an Emergent-like Universe from Modified Gravity: Reconstruction and Phenomenology Optimization with a Genetic Algorithm
• Manifestly Unitary Cosmological Perturbation Theory