Beyond Vanilla Cosmology: The Search for Deviations from
Inflationary Lambda-CDM
Mark Wyman, Perimeter Institute
Abstract:
Cosmology has reached a crossroads. A decade of high- quality data has established a cosmological standard model. At
present, six well-measured parameters can explain many disparate
observations. But the theory behind this model is far from clear. Our
current model, successful though it is, is not firmly tied to
fundamental physics. There is no lack of ideas, however. Many
proposals are exotic: Do we live on a brane in extra spatial
dimensions? Are cosmic strings our best hope for learning about the
inflationary epoch?
To be compelling, new theories must make novel, testable predictions
of unexpected phenomena. In this colloquium, I will review some such
theoretical ideas, emphasizing testable predictions made in my own
work. I will demonstrate that cosmic strings can be made after
inflation. These strings can produce observable B-mode polarization
in the cosmic microwave background radiation. I will also show that
gravity is different if there are more than 3 spatial dimensions.
This kind of modification changes structure formation in ways
observable by upcoming astronomical surveys.