Abstract
We explore trace-anomaly driven inflation in modified gravity. It is explicitly shown that in T2 teleparallel gravity, the de Sitter inflation can occur, although quasi de Sitter inflation happens in R2 gravity. Furthermore, we investigate the influence of the trace anomaly on inflation. It is found that in f(T) gravity, the de Sitter inflation can end because it becomes unstable due to the trace anomaly, whereas also in higher derivative gravity, the de Sitter inflation can be realized and it will be over owing to the trace anomaly for smaller parameter regions in comparison with those in teleparallelism. The instability of the de Sitter inflation in T2 gravity and R2 gravity (both with taking account of the trace anomaly) is examined. In addition, we study trace-anomaly driven inflation in minimal massive bigravity, where the contribution from the massive graviton acts as negative cosmological constant. It is demonstrated that the de Sitter inflation can occur and continue for long enough duration.
Highlights
For a long time, it is expected that vacuum quantum effects and/or quantum gravity effects should play an important role in the early-time cosmological evolution [1,2]
In the present Letter, we have studied trace-anomaly driven inflation in T 2 teleparallel gravity
It has clearly been demonstrated that the de Sitter inflation can be realized in T 2 gravity, while realistic quasi de Sitter inflation occurs in R2 gravity
Summary
It is expected that vacuum quantum effects and/or quantum gravity effects should play an important role in the early-time cosmological evolution [1,2] It was realized in [3] that quantum effects due to conformally invariant fields (conformal or trace-anomaly induced effective action) which is expected to be most relevant at the early universe may lead to the earlytime de Sitter universe. We explore trace-anomaly driven inflation in other modified gravity, i.e., in minimal massive bigravity It has recently been presented the non-linear ghost-free massive gravity (de Rham, Gabadadze, and Tolley (dRGT)) model [30,31]). We study trace-anomaly driven inflation in minimal massive bigravity, where it is demonstrated that the massive term acts as negative cosmological constant.
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