Analogue cosmological particle creation in an ultracold quantum fluid of light

Understand

In inflationary cosmology, the rapid expansion of the early universe resulted in the spontaneous production of cosmological particles from vacuum fluctuations, observable today in the cosmic microwave background anisotropies.

• The analogue of cosmological particle creation in a quantum fluid could provide insight, but an observation has not yet been achieved.
• Here we report the spontaneous creation of analogue cosmological particles in the laboratory, using a quenched 3-dimensional quantum fluid of light.
• We observe acoustic peaks in the density power spectrum, in close quantitative agreement with the quantum-field theoretical prediction.