We probe small scalar coupling differences via the coherent interactions between two nuclear spin singlet states in organic molecules. We show that the spin-lock induced crossing (SLIC) technique enables the coherent transfer of singlet order between one spin pair and another. The transfer is mediated by the difference in cis and trans vicinal J couplings among the spins. By measuring the transfer rate, we calculate a J coupling difference of 8±2 mHz in phenylalanine-glycine-glycine and 2.57±0.04 Hz in glutamate. We also characterize a coherence between two singlet states in glutamate, which may enable the creation of a long-lived quantum memory.
Cite
@article{arxiv.1509.02240,
title = {Probing Scalar Coupling Differences via Long-Lived Singlet States},
author = {Stephen J. DeVience and Ronald L. Walsworth and Matthew S. Rosen},
journal= {arXiv preprint arXiv:1509.02240},
year = {2016}
}