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arXiv · 1606.00618

Jeans' Ghost

A. Emir Gumrukcuoglu·Shinji Mukohyama·Thomas P. Sotiriou
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Abstract

We show that a massless canonical scalar field minimally coupled to general relativity can become a tachyonic ghost at low energies around a background in which the scalar's gradient is spacelike. By performing a canonical transformation we demonstrate that this low energy ghost can be recast, at the level of the action, in a form of a fluid that undergoes a Jeans-like instability affecting only modes with large wavelength. This illustrates that low-energy tachyonic ghosts do not lead to a catastrophic quantum vacuum instability, unlike the usual high-energy ghost degrees of freedom.

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A. Emir Gumrukcuoglu, Shinji Mukohyama, Thomas P. Sotiriou. 2016-06-02. Jeans' Ghost. https://doi.org/10.1103/physrevd.94.064001

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