1、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 sc
2、ale,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 lab,string theory,primordial gravitational wave can be non-trivial?,inflationary gravitational wave,BICEP2/Keck and Planck 2015,the low-energy effective action of heterotic
3、string is Metsaev,Tseytlin, Nucl.Phys.B293, 385 (1987),一个例子：,二、我们的工作,The primordial GW,The effect is negligible, if and,Beyond GR,the effective Planck scalethe propagating speed,The change of speed,The change of speed may be non-trivial.,Gasperini,Veneziano 2002,The effect of non-trivial change of s
4、peed,The equation is,the mode is in Bunch-Davis state,Initially,this sets,Inflation background,The perturbation is ,and are determined by the matching conditions.,Inflation background,The result of primordial GWs,is that of slow-roll inflation,The character scale,Detail of the GWs,However, the oscil
5、lation appear for,is inflationary-like,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,Th
6、e 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 r0.01.,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,r =0.05+lense By Yu-Tong Wang,The outlook:,Tegmark, ApJ 464, L35 1996,WMAP 3-year 2006,Planck 2015,The history of CMB TT spectrum observations,Thank You !,
