1. Lessons from the trace of the energy momentum tensor on inflation models.
- Author
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Kamada, Ayuki, Tou, Teck-Yong, Yokoyama, Jun'ichi, Shukor, Roslan Abdul, Tanaka, Kazuhiro, Choi, Hyoung Joon, Matsumoto, Ryoji, Chin, Oi-Hoong, Chin, Jia Hou, and Ratnavelu, Kuru
- Subjects
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RENORMALIZATION group , *PRICE inflation , *SCALAR field theory , *INFLATIONARY universe , *DEGREES of freedom , *POINT set theory - Abstract
In this note, we discuss properties of the trace of the energy-momentum tensor and their implications for inflation models. One property is the decoupling of heavy degrees of freedom from low-energy dynamics. This is intuitively apparent from the effective field theory point of view, but one has to take into account the so-called trace anomaly to explicitly demonstrate the decoupling. It is relevant to scalaron decay in R2 inflation models. Another is a quantum contribution to a non-minimal coupling of a scalar field to gravity. It might modify inflation dynamics. The non-minimal coupling disappears from the action in the flat spacetime, but leaves the so-called improvement term in the trace of energy momentum tensor. We discuss the "natural" value of a non-minimal coupling from the renormalization group point of view. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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