TY - JOUR
T1 - Quantum non-linear evolution of inflationary tensor perturbations
AU - Gong, Jinn Ouk
AU - Seo, Min Seok
N1 - Funding Information:
We thank Toshifumi Noumi, Gary Shiu, Jiro Soda, Yuko Urakawa and Jaiyul Yoo for discussions while this work was under progress. JG is supported in part by the Basic Science Research Program through the National Research Foundation of Korea Research Grant (2016R1D1A1B03930408). JG 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 (2018K2A9A2A08000127).
Publisher Copyright:
© 2019, The Author(s).
PY - 2019/5/1
Y1 - 2019/5/1
N2 - We study the quantum mechanical evolution of the tensor perturbations during inflation with non-linear tensor interactions. We first obtain the Lindblad terms generated by non-linear interactions by tracing out unobservable sub-horizon modes. Then we calculate explicitly the reduced density matrix for the super-horizon modes, and show that the probability of maintaining the unitarity of the squeezed state decreases in time. The decreased probability is transferred to other elements of the reduced density matrix including off-diagonal ones, so the evolution of the reduced density matrix describes the quantum-to-classical transition of the tensor perturbations. This is different from the classicality accomplished by the squeezed state, the suppression of the non-commutative effect, which is originated from the quadratic, linear interaction, and also maintains the unitarity. The quantum-to-classical transition occurs within 5–10 e-folds, faster than the curvature perturbation.
AB - We study the quantum mechanical evolution of the tensor perturbations during inflation with non-linear tensor interactions. We first obtain the Lindblad terms generated by non-linear interactions by tracing out unobservable sub-horizon modes. Then we calculate explicitly the reduced density matrix for the super-horizon modes, and show that the probability of maintaining the unitarity of the squeezed state decreases in time. The decreased probability is transferred to other elements of the reduced density matrix including off-diagonal ones, so the evolution of the reduced density matrix describes the quantum-to-classical transition of the tensor perturbations. This is different from the classicality accomplished by the squeezed state, the suppression of the non-commutative effect, which is originated from the quadratic, linear interaction, and also maintains the unitarity. The quantum-to-classical transition occurs within 5–10 e-folds, faster than the curvature perturbation.
KW - Cosmology of Theories beyond the SM
KW - Effective Field Theories
UR - http://www.scopus.com/inward/record.url?scp=85065230056&partnerID=8YFLogxK
U2 - 10.1007/JHEP05(2019)021
DO - 10.1007/JHEP05(2019)021
M3 - Article
AN - SCOPUS:85065230056
SN - 1126-6708
VL - 2019
JO - Journal of High Energy Physics
JF - Journal of High Energy Physics
IS - 5
M1 - 21
ER -