Non-Gaussianity from Lifshitz scalar
Non-Gaussianity from Lifshitz scalar
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DOI：
10.1088/1475-7516/2010/10/031
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发表时间：
2010
影响因子：
6.4
通讯作者：
Keisuke Izumi;Takeshi Kobayashi;Shinji Mukohyama
中科院分区：
文献类型：
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作者：
Keisuke Izumi;Takeshi Kobayashi;Shinji Mukohyama
具有动力学临界指数z = 3的Lifshitz标量获得标度不变的超视界场涨落，而不需要暴胀时代。由于这种机制是由于特殊的缩放的Lifshitz标量和持续存在的未抑制的自耦合，由此产生的波动谱可以偏离高斯分布。我们研究了Lifshitz标量的内禀场波动的非高斯性质，并表明源自这种场波动的原始曲率扰动可以具有fNL = O（100）阶的大非高斯性，这将被即将到来的CMB观测所检测到。计算了涨落的双谱和三谱，并讨论了它们在动量空间中的组态。特别是，双谱被发现采取各种形状，包括本地，等边，和正交的形状。有趣的是，所有的积分在in-in形式主义可以进行分析。
A Lifshitz scalar with the dynamical critical exponent z = 3 obtains scale-invariant, super-horizon field fluctuations without the need of an inflationary era. Since this mechanism is due to the special scaling of the Lifshitz scalar and persists in the presence of unsuppressed self-couplings, the resulting fluctuation spectrum can deviate from a Gaussian distribution. We study the non-Gaussian nature of the Lifshitz scalar's intrinsic field fluctuations, and show that primordial curvature perturbations sourced from such field fluctuations can have large non-Gaussianity of order fNL = O(100), which will be detected by upcoming CMB observations. We compute the bispectrum and trispectrum of the fluctuations, and discuss their configurations in momentum space. In particular, the bispectrum is found to take various shapes, including the local, equilateral, and orthogonal shapes. Intriguingly, all integrals in the in-in formalism can be performed analytically.