Natural inflation, strong dynamics, and the role of generalized anomalies

Abstract

We revisit models of natural inflation and show that the single-field effective theory described by the potential $V(a)\sim \cos \frac{a}{f}$ breaks down as the inflaton $a$ makes large-field excursions, even for values of $f$ smaller than the Planck scale. In order to remedy the problem, we modify the potential in order to account for the heavy degrees of freedom (hadrons) that become intertwined with the light inflaton as the latter rolls down its potential. By embedding the low energy degrees of freedom into an ultraviolet complete gauge theory, we argue that the intertwining between the two scales can be explained as the result of a generalized mixed 't Hooft anomaly between the discrete chiral symmetry and background fractional fluxes in the baryon number, color, and flavor directions. Further, we study the multi-field inflation and show that it entertains rich dynamics. Inflating near the hilltop excites the hadrons and spoils the slow-roll parameters, in contradistinction with the expectations in the single-field inflation. Nevertheless, we identify a safe zone where inflation can proceed successfully. We determine the conditions under which the Universe inflates by at least $60$ e-foldings and inflation leads to a power spectrum and tensor to scalar ratio that are consistent with the Cosmic Microwave Background data.

arXiv comment15 pages, comments added, references added, matches the published version

References in corpus (31)

• Electric-Magnetic Duality in Supersymmetric Non-Abelian Gauge Theories
• Generalized Global Symmetries
• The QCD axion, precisely
• Natural Inflation: Particle Physics Models, Power Law Spectra for Large Scale Structure, and Constraints from COBE
• Completing Natural Inflation
• Coupling a QFT to a TQFT and Duality
• N-flation
• Theta, Time Reversal, and Temperature
• Naturally inflating on steep potentials through electromagnetic dissipation
• Chromo-Natural Inflation: Natural inflation on a steep potential with classical non-Abelian gauge fields
• N-flationary magnetic fields
• Center-stabilized Yang-Mills theory: confinement and large $N$ volume independence
• A review of Axion Inflation in the era of Planck
• Transplanckian axions !?
• New Methods in QFT and QCD: From Large-N Orbifold Equivalence to Bions and Resurgence
• A little inflation in the early universe at the QCD phase transition
• Hamilton's approach in cosmological inflation with an exponential potential and its observational constraints
• How Many $e$-Folds Should We Expect from High-Scale Inflation?
• QCD Vacuum and Axions: What's Happening?
• Domain Walls in QCD
• On the baryon-color-flavor (BCF) anomaly in vector-like theories
• Trajectories with suppressed tensor-to-scalar ratio in Aligned Natural Inflation
• Domain Walls and Theta Dependence in QCD with an Effective Lagrangian Approach
• Generalized 't Hooft anomalies on non-spin manifolds
• Notes on natural inflation
• Monodromy Inflation in SUSY QCD
• Deconfinement on axion domain walls
• Axion potential, topological defects and CP-odd bubbles in QCD
• Cosmological perturbations in \bar{QCD}- inflation. Estimates confronting the observations, including BICEP2
• Phases of Inflation
• Strong Dynamics and Natural Inflation

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