2019/06/21 by Jianbo Lu, Xin Zhao, Guoying Chee · 1 citation
Physics and Astronomy · #gr-qc
published as Eur. Phys. J. C (2019) 79:530 · 13 pages, 2 figures. arXiv admin note: text overlap with arXiv:1806.10437, arXiv:1301.0865 by other authors
arxiv created 2019/06/21 · arxiv updated 2019/06/24
We explore an extension of the symmetric teleparallel gravity denoted the f(Q) theory, by considering a function of the nonmetricity invariant Q as the gravitational Lagrangian. Some interesting properties could be found in the f(Q) theory by comparing with the f(R) and f(T) theories. The field equations are derived in the f(Q) theory. The cosmological application is investigated. In this theory the accelerating expansion is an intrinsic property of the universe geometry without need of either exotic dark energy or extra fields. And the state equation of the geometrical dark energy can cross over the phantom divide line in the f(Q) theory. In addition, the dynamical system method are investigated. It is shown that there are five critical points in the STG model for taking f(Q)=Q+αQ2. The critical points P4 and P5 are stable. P4 corresponds to the geometrical dark energy dominated de Sitter universe (wtoteff=-1), while P5 corresponds to the matter dominated universe (wtoteff=0). Given that P4 represents an attractor, the cosmological constant problems, such as the fine tuning problem, could be solved in the STG model.