JQI-QuICS-CMTC Lunch Seminar
Lunch served at 12:00
In standard cosmology, the expansion of the early universe occurs at a speed larger than the speed of light. This expansion also impacts many of the quantum fields that exist inside our universe. Our experiment consisting of neutral $^{23}$Na Bose-Einstein condensate trapped in an all optical ring realizes the basic features of this expansion. Specifically, we demonstrate redshifting of phonons and a reheating effect that is similar to pre-heating after the inflation stage of the universe. We also observe spontaneous non-zero winding numbers appear in the ring after the expansion is complete. We predict the widths of the resulting winding number distributions using Monte Carlo simulations according to the geodesic rule. Our experimental data agrees well with our theory, with no tunable parameters.