Strong Quantum Spin Correlations Observed in Atomic Spin Mixing

TL;DR

This paper reports the experimental observation of strong quantum spin correlations in a spin-1 Bose-Einstein condensate, demonstrating significant noise reduction below the standard quantum limit through atomic spin mixing.

Contribution

It provides the first measurement of sub-Poissonian spin correlations in atomic spin mixing with a notable noise reduction, advancing quantum many-body physics understanding.

Findings

Achieved -7 dB quantum noise reduction below SQL

Detected spin fluctuations via fluorescent imaging with low detection noise

Observed collisionally induced spin mixing in a Bose-Einstein condensate

Abstract

We have observed sub-Poissonian spin correlations generated by collisionally induced spin mixing in a spin-1 Bose-Einstein condensate. We measure a quantum noise reduction of -7 dB (-10 dB corrected for detection noise) below the standard quantum limit (SQL) for the corresponding coherent spin states. The spin fluctuations are detected as atom number differences in the spin states using fluorescent imaging that achieves a detection noise floor of 8 atoms per spin component for a probe time of 100 $\mu$s.