Abstract
Abstract
Two-field mimetic gravity was recently realized by looking at the singular limit of the conformal transformation between the auxiliary metric and the physical metric with two scalar fields involved. In this paper, we reanalyze the singular conformal limit and find a more general solution for the conformal factor A, which greatly broadens the form of two-field mimetic constraint and thus extends the two-field mimetic gravity. We find the general setup still mimics the role of dark matter at the cosmological background level. Moreover, we extend the action by introducing extra possible term for phenomenological interests. Surprisingly, some special cases are found to be equivalent to general relativity, k-essence theory and Galileon theory. Finally, we further extend the theory by allowing the expression of mimetic constraint to be arbitrary without imposed condition, and show that the dark matter-like behavior is unaffected even in this extension.
Publisher
Springer Science and Business Media LLC
Subject
Nuclear and High Energy Physics
Reference73 articles.
1. A. Joyce, B. Jain, J. Khoury and M. Trodden, Beyond the cosmological standard model, Phys. Rept. 568 (2015) 1 [arXiv:1407.0059] [INSPIRE].
2. E. Berti et al., Testing general relativity with present and future astrophysical observations, Class. Quant. Grav. 32 (2015) 243001 [arXiv:1501.07274] [INSPIRE].
3. K. Koyama, Cosmological tests of modified gravity, Rept. Prog. Phys. 79 (2016) 046902 [arXiv:1504.04623] [INSPIRE].
4. Y.-F. Cai, S. Capozziello, M. De Laurentis and E.N. Saridakis, f(T) teleparallel gravity and cosmology, Rept. Prog. Phys. 79 (2016) 106901 [arXiv:1511.07586] [INSPIRE].
5. M. Novello and S.E.P. Bergliaffa, Bouncing cosmologies, Phys. Rept. 463 (2008) 127 [arXiv:0802.1634] [INSPIRE].