Mode-Coupling Cosmic Variance and Tests of Inflation

该奖项为宾夕法尼亚州立大学的Sarah Shandera教授的研究活动提供资金。 有很好的，如果间接的，证据表明，我们的宇宙经历了一个非常快速的膨胀（通货膨胀）的早期阶段，为我们目前观察到的宇宙学的演变奠定了基础。虽然我们期望暴胀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精确的理解。粒子的相互作用可以通过它们在不同尺度上诱导宇宙密度场的可观测性质的耦合来约束。这个研究项目探讨了尺度之间的耦合的影响，这些尺度是我们目前宇宙学窗口之外的尺度。特别是，PI将研究在宇宙的有限体积中进行的观测如何约束暴胀的粒子物理模型，这些模型在更大的不可观测的体积中预测统计数据。PI还将根据理解宇宙的大小和动态演化的主题为小学和高中学生开发研讨会模块。PI已经表明，当在非常不同的尺度上的曲率不均匀性耦合时，我们观测到的宇宙与更大的后暴胀体积的平均预测相比，可能具有有偏差的统计数据。换句话说，在将哈勃体积中的观测与理论进行比较时，存在一个新的宇宙方差来源。通过这笔赠款，PI建议进一步发展约束相互作用暴胀理论的框架，与有限宇宙中的观测兼容。她将绘制出从耦合到超视界模式的宇宙变化在多大程度上可以增加新的不确定性，将原始标量曲率不均匀性的测量结果与理论预测进行比较。她将研究出粒子物理学暴胀场景的哪些定性方面可以被宇宙方差模仿或掩盖。

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.