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arXiv · 1704.06834

On (in)stabilities of perturbations in mimetic models with higher derivatives

Yunlong Zheng·Liuyuan Shen·Yicen Mou·Mingzhe Li
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Abstract

Usually when applying the mimetic model to the early universe, higher derivative terms are needed to promote the mimetic field to be dynamical. However such models suffer from the ghost and/or the gradient instabilities and simple extensions cannot cure this pathology. We point out in this paper that it is possible to overcome this difficulty by considering the direct couplings of the higher derivatives of the mimetic field to the curvature of the spacetime.

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Yunlong Zheng, Liuyuan Shen, Yicen Mou, Mingzhe Li. 2017-04-22. On (in)stabilities of perturbations in mimetic models with higher derivatives. https://doi.org/10.1088/1475-7516%2F2017%2F08%2F040

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