Analytical Methods for Inflation Correlators.
- Zhehan Qin, Tsinghua University
The correlation functions of large-scale fluctuations are crucial observables in modern cosmology. These boundary correlators contain rich information about the bulk dynamics and can be used to probe physics at the inflation scale. There have been considerable efforts in the analytical study of inflation correlators in recent years. In this talk, I will introduce the basic structure of inflation correlators and several analytical methods we have developed for their computation. In particular, I will introduce the method of partial Mellin-Barnes (PMB) representation. With this method, we can largely solve the massive tree correlators analytically. At the loop level, we use PMB to prove a factorization theorem for the nonanalytical part of inflation correlators, which produces a characteristic nonlocal signal. Finally, we can recover the full correlator starting from this nonanalytical part using a dispersion integral.
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