Related Experiment Video
Updated: Sep 13, 2025

Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
Published on: December 3, 2013
Gaussian-to-Non-Gaussian Transition of a Quantum Spin Bath Revealed by Fourth-Order Correlation
Fan Xia1,2, Shuowei Li3, Xin-Yu Pan1,2,4
1Institute of Physics, Chinese Academy of Sciences, Beijing National Laboratory for Condensed Matter Physics, Beijing 100190, China.
None:
Non-Gaussian fluctuations are one of the essential properties of quantum systems. However, the direct detection of non-Gaussian fluctuations has not yet been achieved in experiments since the specific order of correlation has to be isolated from the complex dynamics of the whole system. In this Letter, we measure the second- and fourth-order correlations of ^{13}C nuclear spins around a nitrogen vacancy center in diamond, using the recently developed quantum nonlinear spectroscopy. By adjusting the detection window and the spectral resolution, we observe the Gaussian to non-Gaussian transition of the multispin system. We find that the fourth-order correlation provides a fingerprint signal that can be used to identify individual spins with the same precession frequency, suggesting that Gaussianity is a potential quantum resource for quantum sensing. Our results shed light on the study of nonequilibrium quantum many-body dynamics and quantum materials at the nanoscale.
Related Concept Videos
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
Atomic Nuclei: Nuclear Relaxation Processes
Spin–Spin Coupling Constant: Overview
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
NMR Spectroscopy: Spin–Spin Coupling
Atomic Nuclei: Types of Nuclear Relaxation
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
Atomic Nuclei: Nuclear Spin State Population Distribution

