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(Seminar) Gauge Invariance of Scalar Induced Gravitational Waves ( 标量扰动诱导的引力波及其规范不变性)

11/11 2020
  • Title (Seminar) Gauge Invariance of Scalar Induced Gravitational Waves ( 标量扰动诱导的引力波及其规范不变性)
  • Speaker
  • Date
  • Venue
    • Abstract

    CAS Key Laboratory of Theoretical Physics

    Institute of Theoretical Physics

    Chinese Academy of Sciences

     Seminar

    Title

    题目

    		 Gauge Invariance of Scalar Induced Gravitational Waves (标量扰动诱导的引力波及其规范不变性)

    Speaker

    报告人
    王赛 副研究员
    2009年本科毕业于华中科技大学，2014年博士毕业于中国科学院大学，先后在高能物理所、理论物理所、香港中文大学、日本高能加速器研究机构（KEK）开展引力和宇宙学研究。2019年入职高能物理所。目前致力于引力波宇宙学方面的研究工作。

    Affiliation

    所在单位

    		 高能物理所理论物理室

    Date

    日期

    		 November 11 (Wednesday) 3:00 pm

    Venue

    地点

    		  6420

    Contact Person

    所内联系人

    		 皮石

    Abstract

    摘要

    		 We investigate the gauge invariance of the second order gravitational waves induced by the first order scalar perturbations by following the Lie derivative method. It is shown explicitly that the second order gravitational waves are gauge invariant in the synchronous frame. In the gauge invariant framework, we derive the equation of motion of the second order gravitational waves and show that the second order gravitational waves are sourced from the first order scalar perturbations described well in the gauge invariant Newtonian frame. Since the observables of gravitational waves are measured in the synchronous frame, we define the energy density spectrum of the second order gravitational waves in terms of the gauge invariant synchronous variables. This way guarantees no fictitious tensor perturbations. It is shown that the gauge invariant energy density spectrum of the second order gravitational waves coincides with the one in the Newtonian gauge.