Planck Satellite Constraints on Pseudo-Nambu--Goldstone Boson Quintessence

Understand

The Pseudo-Nambu-Goldstone Boson (PNGB) potential, defined through the amplitude $M^4$ and width $f$ of its characteristic potential $V(\phi) = M^4[1 + \cos(\phi/f)]$, is one of the best-suited models for the study of thawing quintessence.

• We analyze its present observational constraints by direct numerical solution of the scalar field equation of motion.
• Observational bounds are obtained using Supernovae data, cosmic microwave background temperature, polarization and lensing data from {\it Planck}, direct Hubble constant constraints, and baryon acoustic oscillations data.
• We find the parameter ranges for which PNGB quintessence gives a viable theory for dark energy.