# Parametric amplification of vacuum fluctuations in a spinor condensate

## TL;DR

This paper demonstrates the parametric amplification of vacuum fluctuations in a spinor Bose-Einstein condensate, highlighting the role of quantum vacuum in matter wave pair creation and its potential for generating non-classical states.

## Contribution

It provides experimental evidence of vacuum fluctuation amplification in a spinor condensate and shows the process's robustness against classical seeding at high magnetic fields.

## Key findings

- Pair creation occurs from vacuum fluctuations in a spinor condensate.
- The process is insensitive to classical seeds at high magnetic fields.
- The system enables generation of non-classical matter states.

## Abstract

Parametric amplification of vacuum fluctuations is crucial in modern quantum optics, enabling the creation of squeezing and entanglement. We demonstrate the parametric amplification of vacuum fluctuations for matter waves using a spinor F=2 Rb-87 condensate. Interatomic interactions lead to correlated pair creation in the m_F= +/- 1 states from an initial unstable m_F=0 condensate, which acts as a vacuum for m_F unequal 0. Although this pair creation from a pure m_F=0 condensate is ideally triggered by vacuum fluctuations, unavoidable spurious initial m_F= +/- 1 atoms induce a classical seed which may become the dominant triggering mechanism. We show that pair creation is insensitive to a classical seed for sufficiently large magnetic fields, demonstrating the dominant role of vacuum fluctuations. The presented system thus provides a direct path towards the generation of non-classical states of matter on the basis of spinor condensates.