Speaker
Description
The early universe has undergone a transition from a super-cooled
state after cosmic inflation to a hot and thermal one. We propose an analog
experimental implementation of this cosmic reheating dynamics using an
ultra-cold Bose gas. In our mapping, a Bose-Einstein condensate plays the
role of the inflaton field, which describes the state of the universe after
inflation. The expansion of the universe as well as the dynamics of the
inflaton field are encoded in the time-dependence of the atomic interaction,
which can be tuned via Feshbach resonances. By means of
classical-statistical simulations we illustrate that the dynamics of the
system involves the known stages of reheating. At early times, parametric
instabilities lead to the production of Bogoliubov quasi-particles as
excitations on top of the condensate, mimicking cosmological particle
production by the decaying inflaton field. At later times, the system
develops a turbulent cascade transporting energy to higher momenta in a
self-similar way. The final stage of the dynamics, where the system relaxes
to thermal equilibrium, is dominated by quantum fluctuations and therefore
not captured by the classical-statistical approximation, which motivates an
experimental study of this process using a quantum simulator."