Zhehan Qin - Cosmological Correlators at the Loop Level
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- Опубликовано: 17 дек 2024
- Abstract: "During cosmic inflation, the equal-time correlators of massless inflaton fluctuations encode physics at the Hubble scale. These cosmological correlators open a new window to detect high-energy physics at the inflation scale. In particular, heavy particles will leave characteristic imprints on these correlators due to their interactions with inflatons, known as the cosmological collider signals. However, calculating these correlators and their signals is difficult because of the spacetime curvature, though a few methods have been developed with remarkable progress.
In this talk, I will briefly introduce the partial Mellin-Barnes (PMB) representation, which has proven useful for general tree-level calculations. Then I will show how it works for loop-level diagrams. With the PMB representation, we can analytically derive the full signal of a bubble diagram, even without the requirement of full dS isometries. I will also comment on the background piece and the regularization. This shows that PMB representation is also powerful at loop levels, which can help us build accurate templates for future cosmic observations, and give us more insights into understanding quantum field theories in de Sitter spacetime."