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Low-energy Low-energy effective string theory effective string theory in primordial gravitational wave in primordial gravitational wave 朴云松 University of CAS USTC-ICTS , 2015.4.23
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一、动机 二、我们的工作 三、讨论 Based on 1501.06345, PRD, with Yong Cai and Yu-Tong Wang
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The paradigm of early universe: inflation (alternatives ?)
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Planck 2015 results
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As a laboratory inflation sub-Planck scale LHC ?
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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
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inflationary lab string theory primordial gravitational wave can be non-trivial? inflationary gravitational wave BICEP2/Keck and Planck 2015
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the low-energy effective action of heterotic string is Metsaev,Tseytlin, Nucl.Phys.B293, 385 (1987) 一个例子:
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二、 我们的工作
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The primordial GW The effect is negligible, if and Beyond GR the effective Planck scale the propagating speed
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The change of speed may be non-trivial. Gasperini,Veneziano 2002
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The effect of non-trivial change of speed The equation is
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the mode is in Bunch-Davis state Initially, this sets Inflation background
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The perturbation is, and are determined by the matching conditions. Inflation background
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The result of primordial GWs is that of slow-roll inflation The character scale
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Detail of the GWs However, the oscillation appear for is inflationary-like
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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
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Transfer to B-mode polarization spectrum l=2,65
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is the optical depth
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三、 Discussion
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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.
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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
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r =0.05+lense By Yu-Tong Wang The outlook:
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Tegmark, ApJ 464, L35 1996 WMAP 3-year 2006 Planck 2015 The history of CMB TT spectrum observations
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Thank You !
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