Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Low-energy effective string theory in primordial gravitational wave 朴云松 University of CAS USTC-ICTS,2015.4.23 一、动机 二、我们的工作 三、讨论 Based on 1501.06345, PRD, with Yong Cai and Yu-Tong Wang The paradigm of early universe: inflation (alternatives ?) Planck 2015 results As a laboratory ? inflation sub-Planck scale LHC 1、Primordial scalar perturbation Planck限制, 原初的 “污染”源多 2、Primordial gravitational wave 目前只有上限, 没有原初的“污染”源 inflationary gravitational wave BICEP2/Keck and Planck 2015 inflationary lab string theory primordial gravitational wave can be non-trivial? 一个例子: the low-energy effective action of heterotic string is Metsaev,Tseytlin, Nucl.Phys.B293, 385 (1987) 二、我们的工作 The primordial GW Beyond GR the effective Planck scale the propagating speed The effect is negligible, if and The change of speed Gasperini,Veneziano 2002 The change of speed may be non-trivial. The effect of non-trivial change of speed The equation is Inflation background Initially, the mode is in Bunch-Davis state this sets Inflation background and are determined by the matching conditions. The perturbation is , The result of primordial GWs The character scale is that of slow-roll inflation Detail of the GWs is inflationary-like However, the oscillation appear for The oscillation can be attributed to other mechanism? 1、 is oscillating, hardly implemented. 2、The production of particles, only a bump-like behavior. Gary Shiu et.al 1405.0346 Transfer to B-mode polarization spectrum l=2,65 is the optical depth 三、Discussion The assumptions: 1、Inflation is the paradigm of early universe. 2、The higher-order derivative terms in superstring theory is significant. alter The conclusion: The oscillating GWs is imprinted in CMB B-mode polarization. Hope r>0.01. The physics of oscillation The low-energy effective action of superstring alters the initial state of mode The Bunch-Davis state only for mode but for mode Note: initial state is not altered by The outlook: r =0.05+lense By Yu-Tong Wang WMAP 3-year 2006 Tegmark, ApJ 464, L35 1996 The history of CMB TT spectrum observations Planck 2015 Thank You !