TY - JOUR

T1 - Stable cosmological solutions in degenerate theory of gravity

AU - Kase, Ryotaro

AU - Kimura, Rampei

AU - Naruko, Atsushi

AU - Yoshida, Daisuke

N1 - Funding Information:
R. Kimura and D.Y. thank Masahide Yamaguchi for many useful comments and discussions. R. Kase and A.N. would like to thank the Yukawa Institute for Theoretical Physics at Kyoto University, where discussions during the YITP symposium YKIS2018a “General Relativity – The Next Generation” were useful to complete this work. This work was supported in part by JSPS Grant-in-Aid for Scientific Research Nos. JP17K14297 (R. Kase), JP17K14276 (R. Kimura), JP25287054 (R. Kimura) and JSPS Postdoctoral Fellowships for Research Abroad (D.Y.). A.N. is supported in part by a Japan Science and Technology Agency grant “Establishing a Consortium for the Development of Human Resources in Science and Technology”. The work of A.N. is also partly supported by the JSPS Grant-in-Aid for Scientific Research No. 16H01092 .

PY - 2018/8/10

Y1 - 2018/8/10

N2 - We study cosmological applications of extended vector–tensor theories, whose Lagrangians contain up to two derivatives with respect to metric and vector field. We derive background equations under the assumption of homogeneous and isotropic universe and study the nature of cosmological perturbations on top of the background. We found an example of healthy cosmological solutions in non-trivial degenerate theory of gravity for the first time, where those perturbations do not suffer from any instabilities, that is, ghost and gradient instabilities.

AB - We study cosmological applications of extended vector–tensor theories, whose Lagrangians contain up to two derivatives with respect to metric and vector field. We derive background equations under the assumption of homogeneous and isotropic universe and study the nature of cosmological perturbations on top of the background. We found an example of healthy cosmological solutions in non-trivial degenerate theory of gravity for the first time, where those perturbations do not suffer from any instabilities, that is, ghost and gradient instabilities.

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U2 - 10.1016/j.physletb.2018.07.009

DO - 10.1016/j.physletb.2018.07.009

M3 - Article

AN - SCOPUS:85051255380

VL - 783

SP - 320

EP - 325

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

SN - 0370-2693

ER -