Speaker
Description
We present constraints on axion quintessence dark energy using the latest cosmological observations. Focusing on the physical parameters of the model, we find a preferred axion mass of log10(ma/eV)≃−32.6\log_{10}(m_a/{\rm eV}) \simeq -32.6log10(ma/eV)≃−32.6 and a decay constant of log10(fa/MPl)≃0.1\log_{10}(f_a/M_{\rm Pl}) \simeq 0.1log10(fa/MPl)≃0.1. We perform a Bayesian model comparison with the standard cosmological constant scenario and show that axion quintessence provides a competitive description of current data. Motivated by recent observational hints favoring dynamical dark energy, we discuss the implications of these results for the nature of cosmic acceleration and for ultralight axion physics. Finally, we outline the prospects for testing this scenario with forthcoming cosmological surveys and high-precision measurements.