Mode-Coupling Cosmic Variance and Tests of Inflation

该奖项资助宾夕法尼亚州立大学萨拉·香德拉教授的研究活动。有很好的证据表明，即使是间接的，我们的宇宙经历了一个非常迅速的膨胀(膨胀)的早期阶段，这为我们目前观察到的宇宙学的演变奠定了基础。尽管我们预计暴涨可以用粒子物理学来解释，但我们还没有对负责的粒子的性质有一个准确的了解。粒子相互作用可以通过在不同尺度的宇宙密度场的可观测属性中诱导耦合的方式来限制。这项研究项目考察了在我们目前的宇宙窗口之外的尺度上可观察到的尺度之间的耦合的含义。特别是，PI将研究在有限体积的宇宙中进行的观测如何约束膨胀的粒子物理模型，这些模型对更大、不可观测的体积中的统计数据进行预测。PI还将以了解宇宙的大小和动态演化为主题，为中小学生开发研讨会模块。PI已经表明，当非常不同尺度上的曲率不均匀耦合在一起时，我们观察到的宇宙可能会有偏向的统计数据，而不是预测的较大后膨胀后体积的平均值。换句话说，将我们哈勃体积中的观测值与理论进行比较，有了一个新的宇宙差异来源。通过这笔拨款，PI提议进一步发展约束相互作用的膨胀理论的框架，与有限宇宙中的观测相兼容。她将绘制出从耦合到超视界模式的宇宙变化在将原始标量曲率不均匀的测量结果与理论预测进行比较时增加新的不确定性的程度。她将找出粒子物理中关于膨胀的定性方面的哪些方面可以被宇宙变化所模仿或掩盖。

This award funds the research activities of Professor Sarah Shandera at Pennsylvania State University. There is excellent, if indirect, evidence that our universe underwent an early period of very rapid expansion (inflation) which set the stage for the evolution to the cosmology we currently observe. Although we expect that inflation can be explained in terms of particle physics, we do not yet have a precise understanding of the nature of the particles responsible. Particle interactions can be constrained by the way they induce couplings in observable properties of the cosmic density field on different scales. This research project examines the implications of coupling between scales that are observable to scales that are outside of our current cosmological window. In particular, the PI will study how observations made in a finite volume of the universe constrain particle physics models of inflation which make predictions about statistics in a much larger, unobservable, volume. The PI will also develop workshop modules for elementary and high school students based on the theme of understanding the size and dynamical evolution of the universe. The PI has already shown that when the curvature inhomogeneities on very different scales are coupled, our observed universe is likely to have biased statistics compared to the mean predicted for a larger post-inflationary volume. In other words, there is a new source of cosmic variance in comparing observations in our Hubble volume to theory. Through this grant, the PI proposes to further develop the framework for constraining interacting inflation theories, compatible with observations in a finite universe. She will map out the extent to which the cosmic variance from coupling to superhorizon modes can add new uncertainties in comparing measurements of the primordial scalar curvature inhomogeneities to predictions from theory. She will work out which qualitative aspects of particle physics scenarios for inflation can be mimicked or obscured by cosmic variance.