Date: Friday 6th October
Who: Nick Menicucci
Seminar type: Research Seminar
Time: 12 Midday
Where: Interaction Room
Abstract:
The inflationary hypothesis purports to solve several fundamental problems with standard cosmology, including the anisotropy of the cosmic microwave background (CMB). It is argued that quantum fluctuations in the original state of the universe get “frozen out”
during inflation and become classical density fluctuations, which are believed to be the seeds for galaxies and other structure in the universe.
The physical mechanism by which this “freezing out” actually occurs, though, remains a mystery. Ion traps provide a manageable system with which we can study the acoustic analogues of inflationary processes, including the supposed “freezing out” of quantum fluctuations. Phonons play the role of a discretized quantum field, while the overall trap frequency can be chirped to reproduce the effect of an expanding spacetime. The ions’ electronic states are a classically observable field that is coupled to the phonon field through an external laser. Using standard quantum mechanics, spatial correlations in the detected excitation of electronic states can be shown to be a function of quantum correlations in the initial state of the phonon field. This is work in progress with Gerard Milburn. No prior knowledge of cosmology is assumed.