In cosmology, the relativistic scalar fields that cause the universe to expand are damped by Hubble friction, which is due to the dilation of the underlying spacetime metric. Here, we have simulated the Hubble friction using a toroidal Bose-Einstein condensate (BEC) of 23Na atoms, in which the phonon fields can serve as an analogy to the cosmological scalar fields. We experimentally measure both Hubble attenuation and amplification, with five-fold better accuracy, by expanding and contracting the BEC universe. We discover temporal phase-dependent attenuation and amplification of the phonon field, which is only possible under non-adiabatic processes and is not described by the theoretical model. The measured strength of the Hubble friction disagrees with recent theories.
|Presenter name||Yanda Geng|
|How will you attend ICAP-27?||I am planning on in-person attendance|