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Small cosmological constant from running gravitational coupling and f(R) gravity
2011-07-14  【 】【打印】【关闭
Institute of Theoretical Physics
Chinese Academy of Sciences
学术报告
Title
题目
Small cosmological constant from running gravitational coupling and f(R) gravity
Speaker
报告人
郭俊起
Simon Fraser University, Canada
Date
日期
2011-07-14 PM 15:30 Thursday
Venue
地点
Conference Hall 322, ITP/理论物理所322报告厅
Abstract
摘要

In this talk, we explore an idea of having Newton's constant change its value depending on the curvature scale involved. Such modification leads to a scalar-tensor gravity theory, with the Lagrangian derived from renormalization group flow arguments. Assuming running of the (classical) gravitational coupling is described by the same beta function as the (quantum) one in QCD, one is lead to a simple f(R)-type model with several striking features. The model has unique de Sitter attractor, with effective cosmological constant exponentially suppressed relative to Planck scale by inverse of the running parameter. Thus not only cosmological constant appears dynamically in this model, its value is small precisely because the gravity we observe is almost Einstein-like. With the same number of parameters as Lambda-CDM and no excessively small numbers involved, this looks like an interesting cosmological model, and we investigate its dynamics and observational consequences. This talk is mainly based on arXiv:1101.4995v1 [astro-ph.CO].

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