@article{94de962c5cb04cc0ade6b90de0a77a05,
title = "Second-order energy-momentum tensor of a scalar field",
abstract = "We investigate the second-order effective energy-momentum tensor (2EMT) constructed by the quadratic terms of the linear scalar cosmological perturbations while the universe is dominated by a scalar field. We show that 2EMT is gauge dependent. We then study 2EMT in three (longitudinal, spatially flat, and comoving) gauge conditions in the slow-roll stage of inflation. We find that 2EMT exhibits an effective fluid of w=-1/3 on superhorizon scales in all of those gauge conditions.",
author = "Inyong Cho and Gong, {Jinn Ouk} and Oh, {Seung Hun}",
note = "Funding Information: This work is supported in part by the National Research Foundation funded by the Korean government, Grants No. 2020R1A2C1013266 (I. C.), No. 2019R1A2C2085023 (J.-O. G.), and No. 2021R1F1A1063308 (S. H. O.). J.-O. G. also acknowledges the Korea-Japan Basic Scientific Cooperation Program supported by the National Research Foundation of Korea and the Japan Society for the Promotion of Science (No. 2020K2A9A2A08000097). J.-O. G. is supported in part by the Ewha Womans University Research Grant of 2020 (No. 1-2020-1630-001-1), 2021 (No. 1-2021-1227-001-1), and 2022 (No. 1-2022-0606-001-1). J.-O. G. is grateful to the Asia Pacific Center for Theoretical Physics for hospitality while this work was in progress. S. H. O. is supported in part by the Academic Promotion System of Tech University of Korea. Publisher Copyright: {\textcopyright} 2022 American Physical Society.",
year = "2022",
month = oct,
day = "15",
doi = "10.1103/PhysRevD.106.084027",
language = "English",
volume = "106",
journal = "Physical Review D",
issn = "2470-0010",
publisher = "American Physical Society",
number = "8",
}