Quantum-Fluctuation-Driven Coherent Spin Dynamics in Small Condensates

TL;DR

This paper investigates how quantum fluctuations drive coherent spin dynamics in small sodium atom condensates, revealing tunable behaviors that can be observed through coupled atom-photon spectral measurements.

Contribution

It demonstrates that quantum fluctuations, rather than mean field effects, solely drive spin dynamics in small condensates, with tunability via Zeeman coupling and magnetization.

Findings

Quantum fluctuations drive coherent spin oscillations.

Spectral measurements reveal spin population dynamics.

Dynamics are tunable by external magnetic fields.

Abstract

We have studied quantum spin dynamics of small condensates of cold sodium atoms. For a condensate initially prepared in a mean field ground state, we show that coherent spin dynamics are {\em purely} driven by quantum fluctuations of collective spin coordinates and can be tuned by quadratic Zeeman coupling and magnetization. These dynamics in small condensates can be probed in a high-finesse optical cavity where temporal behaviors of excitation spectra of a coupled condensate-photon system reveal the time evolution of populations of atoms at different hyperfine spin states.