We propose to store non-classical states of light into the macroscopic collective nuclear spin (1018 atoms) of a 3He vapor, using metastability exchange collisions. These collisions, commonly used to transfer orientation from the metastable state 23S_1 to the ground state state of 3He, can also transfer quantum correlations. This gives a possible experimental scheme to map a squeezed vacuum field state onto a nuclear spin state with very long storage times (hours).
@article{arxiv.quant-ph/0504152,
title = {Long-lived quantum memory with nuclear atomic spins},
author = {Aurelien Dantan and Gael Reinaudi and Alice Sinatra and Franck Laloë and Elisabeth Giacobino and Michel Pinard},
journal= {arXiv preprint arXiv:quant-ph/0504152},
year = {2016}
}