I recently submitted a new paper to the archive (where ‘pre-print’ copies of a paper go so everyone can access them, even while the peer review journal process proceeds). The title of the paper is ‘Transporting non-Gaussianity from sub to super-horizon scales‘.
The gist is this. During inflation (the accelerated expansion of the universe which we think occurred when the universe was extremely young), small quantum fluctuations on tiny scales are expanded to become classical undulations in the matter distribution and space-time geometry of the universe. These now classical fluctuations go on to collapse to form all structure in the universe (galaxies and clusters of galaxies). In the inflationary phase, when fluctuations behave in a quantum manner we call them sub-horizon perturbations, and when they are large enough to behave in a classical manner we call them super-horizon fluctuations. By measuring the properties of these fluctuations through observation, we learn about inflation. Continue reading