String Theory Seminar
Dr. Liam McAllister, Cornell University
“Quantum Gravity in the Sky? Inflation and String Theory after BICEP2”
The BICEP2 collaboration has recently reported a detection of primordial B-mode polarization in the CMB. If this result is confirmed, it is a discovery of extraordinary significance: the most straightforward interpretation is that the B-modes are the imprint of quantum fluctuations of the gravitational field during a period of inflation at energy densities of order the GUT scale. I will explain the implications of this finding for inflationary cosmology, emphasizing that the BICEP2 detection makes a theory of quantum gravity compulsory for the study of the very early universe. I will then describe how inflation can be realized in string theory, giving an overview of the current status of the subject and explaining the use of string theory in the interpretation of cosmological observations.