Observational constraints on inflection point quintessence with a cubic potential

Abstract

We examine the simplest inflection point quintessence model, with a potential given by $V(\phi) = V_0 + V_3 \phi^3$. This model can produce either asymptotic de Sitter expansion or transient acceleration, and we show that it does not correspond to either pure freezing or thawing behavior. We derive observational constraints on the initial value of the scalar field, $\phi_i$, and $V_3/V_0$ and find that small values of either $\phi_i$ or $V_3/V_0$ are favored. While most of the observationally-allowed parameter space yields asymptotic de Sitter evolution, there is a small region, corresponding to large $V_3/V_0$ and small $\phi_i$, for which the current accelerated expansion is transient. The latter behavior is potentially consistent with a cyclic universe.