Novel matter coupling in general relativity via canonical transformation

Katsuki Aoki, Chunshan Lin, Shinji Mukohyama

    研究成果: Article査読

    28 被引用数 (Scopus)


    We study canonical transformations of general relativity (GR) to provide a novel matter coupling to gravity. Although the transformed theory is equivalent to GR in vacuum, the equivalence no longer holds if a matter field minimally couples to the canonically transformed gravitational field. We find that a naive matter coupling to the transformed field leads to the appearance of an extra mode in the phase space, rendering the theory inconsistent. We then find a consistent and novel way of matter coupling: after imposing a gauge fixing condition, a matter field can minimally couple to gravity without generating an unwanted extra mode. As a result, the way matter field couples to the gravitational field determines the preferred time direction and the resultant theory has only two gravitational degrees of freedom. We also discuss the cosmological solution and linear perturbations around it, and confirm that their dynamics indeed differ from those in GR. The novel matter coupling can be used for a new framework of modified gravity theories.

    ジャーナルPhysical Review D
    出版ステータスPublished - 2018 8月 15

    ASJC Scopus subject areas

    • 物理学および天文学(その他)


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