Cosmological consequences of a scalar field with oscillating equation of state. II. Oscillating scaling and chaotic accelerating solutions

A multiacceleration scenario can be used to solve the cosmological coincidence problem. In this paper, after considering the early radiation era, we revisit the cosmological dynamics of the oscillating dark energy model proposed by Tián [Phys. Rev. D 101, 063531 (2020)]. We find this model allows the Universe to evolve as an oscillating scaling solution (OSS) in the radiation era and as a chaotic accelerating solution (CAS) in the matter era. Mathematically, the transition from OSS to CAS is a route of period-doubling bifurcation to chaos. Physically, there are two reasons to convince us that this scenario can be a nice picture to describe the real Universe. One is the global cosmological parameter constraints are practicable if the Universe evolves as an OSS in the radiation era. The other is the late-time Universe described by a CAS can successfully explain the observed cosmic acceleration at low redshifts.