Inflation after BICEP2

• Main Author: Westphal, Alexander
• Format: Other/Unknown Material
• Language: English
• Published: 2014
• Subjects: Antarc*; Antarctica
• Online Access: https://bib-pubdb1.desy.de/record/172333; https://bib-pubdb1.desy.de/search?p=id:%22PUBDB-2014-03683%22

BICEP2 from Antarctica has given us the first clear evidence for primordial gravitational waves from inflation causing B-mode polarization at degree angular scales $\ell<100$. If interpreted in the context of inflation, their signal corresponds to a tensor-to-scalar ratio $r=0.16^{+0.06}_{−0.05}$, which disfavors $r<0.01$ at about $5\sigma$. We will discuss the implications of this result for models of single-field slow-roll inflation. Due to the Lyth bound, the new data represent strong evidence against virtually all small-field models of inflation. We will discuss the need for protective symmetries such as shift symmetries in large-field inflation models which are now favored, and review the situation of string inflation and its large-field version of (axion) monodromy.