Abstract
We report an observation of long-lived spin-singlet states in a spin pair in a zero magnetic field. In -labeled formic acid, we observe spin-singlet lifetimes as long as 37 s, about a factor of 3 longer than the lifetime of dipole polarization in the triplet state. In contrast to common high-field experiments, the observed coherence is a singlet-triplet coherence with a lifetime longer than the lifetime of dipole polarization in the triplet manifold. Moreover, we demonstrate that heteronuclear singlet states formed between a and a nucleus can exhibit longer lifetimes than the respective triplet states even in the presence of additional spins that couple to the spin pair of interest. Although long-lived homonuclear spin-singlet states have been extensively studied, this is the first experimental observation of analogous singlet states in heteronuclear spin pairs.
- Received 23 September 2013
DOI:https://doi.org/10.1103/PhysRevLett.112.077601
© 2014 American Physical Society
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Vive la Différence!
Published 18 February 2014
Long-lived singlet states—zero-spin states made of two spin- particles—can be created by combining two different atomic species such as carbon and hydrogen.
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