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CAS Key Laboratory of Theoretical Physics
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Institute of Theoretical Physics
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Chinese Academy of Sciences
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Seminar
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Title
題目
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Gauge Invariance of Scalar Induced Gravitational Waves ( 標量擾動誘導的引力波及其規范不變性) |
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Speaker
報告人
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王賽 副研究員
2009年本科畢業于華中科技大學，2014年博士畢業于中國科學院大學，先后在高能物理所、理論物理所、香港中文大學、日本高能加速器研究機構（KEK）開展引力和宇宙學研究。2019年入職高能物理所。目前致力于引力波宇宙學方面的研究工作。 |
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Affiliation
所在單位
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高能物理所理論物理室 |
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Date
日期
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November 11 (Wednesday) 3:00 pm |
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Venue
地點
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6420 |
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Contact Person
所內聯系人
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皮石 |
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Abstract
摘要
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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. |
