Unifying phantom inflation with late-time acceleration: scalar phantom-non-phantom transition model and generalized holographic dark energy

TL;DR

This paper proposes a unified cosmological model combining phantom and non-phantom phases to explain early inflation and late-time acceleration, introducing scalar field transitions and generalized holographic dark energy.

Contribution

It introduces a novel scalar field model allowing phantom-non-phantom transitions and a generalized holographic dark energy framework unifying early and late universe acceleration.

Findings

Scalar field model enables multiple phantom and non-phantom phases.

Generalized holographic dark energy can address the coincidence problem.

Model allows crossing of the phantom divide and unification of inflation and acceleration.

Abstract

The unifying approach to early-time and late-time universe based on phantom cosmology is proposed. We consider gravity-scalar system which contains usual potential and scalar coupling function in front of kinetic term. As a result, the possibility of phantom-non-phantom transition appears in such a way that universe could have effectively phantom equation of state at early time as well as at late time. In fact, the oscillating universe may have several phantom and non-phantom phases. As a second model we suggest generalized holographic dark energy where infrared cutoff is identified with combination of FRW parameters: Hubble constant, particle and future horizons, cosmological constant and universe life-time (if finite). Depending on the specific choice of the model the number of interesting effects occur: the possibility to solve the coincidence problem, crossing of phantom divide and unification of early-time inflationary and late-time accelerating phantom universe. The bound for holographic entropy which decreases in phantom era is also discussed.