Quintessence and spontaneous leptogenesis

We propose in this paper a scenario of spontaneous baryogenesis in cosmological models of quintessence by introducing a derivative coupling of the quintessence scalar Q to the baryon current $J_B^{\mu }$ or the current of the baryon number minus lepton number $J_{B-L}^{\mu }.$ We find that with a dimension-5 operator ${\partial }_{\mu }{\mathrm{QJ}}_{B-L}^{\mu }$ suppressed by the Planck mass $M_{\mathrm{pl}}$ or the grand unification scale $M_{\mathrm{GUT}},$ baryon number asymmetry $n_B/s\sim {10}^{-10}$ can be naturally explained via leptogenesis. We study also the isocurvature baryon number fluctuation generated in our model.