Analogue cosmological particle creation in an ultracold quantum fluid of light

TL;DR

This paper reports the first laboratory observation of analogue cosmological particle creation using a quenched 3D quantum fluid of light, showing acoustic peaks consistent with quantum-field theory predictions, and offers insights into early universe phenomena.

Contribution

It demonstrates the spontaneous creation of analogue cosmological particles in a quantum fluid of light, providing a new platform for studying early universe physics.

Findings

Observation of acoustic peaks in the density power spectrum

Quantitative agreement with quantum-field theoretical predictions

Application of the principle to cosmic microwave background analysis

Abstract

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. We find that the long-wavelength particles provide a window to early times, and we apply this principle to the cosmic microwave background. This work introduces a new quantum fluid, as cold as an atomic Bose-Einstein condensate.