English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Boundary term and Brown-York (BY) formalism, which is based on theHamilton-Jacobi principle, are complimentary of each other as the gravitationalactions are not, usually, well-posed. In scalar-tensor theory, which is animportant alternative to GR, it has been shown that this complementaritybecomes even more crucial in establishing the equivalence of the BY quasi-localparameters in the two frames which are conformally connected. Furthermore,Brown-York tensor and the corresponding quasi-local parameters are importantfrom two important yet different aspects of gravitational theories: black holethermodynamics and fluid-gravity correspondence. The investigation suggeststhat while the two frames are equivalent from the thermodynamic viewpoints,they are not equivalent from the perspective of fluid-gravity analogy or themembrane paradigm. In addition, the null boundary term and null Brown-Yorkformalism are the recent developments (so far obtained only for GR) which isnon-trivial owing to the degeneracy of the null surface. In the presentanalysis these are extended for scalar-tensor theory. The present analysis alsosuggests that, regarding the equivalence (or inequivalence) of the two frame,the null formalism draws the same inferences as of the timelike case, which inturn establishes the consistency of the newly developed null Brown-Yorkformalism.

Boundary terms and Brown-York quasi-local parameters for scalar-tensor theory: a study on both timelike and null hypersurfaces