Abstract
Spin squeezing is a well-established " quantum technology ", where well-chosen correlations in an ensemble of two-level systems reduce the statistical uncertainty of spectroscopic measurements. After an introduction outlining the issues at stake and some important advances in the field, I will outline some promising developments, including the possibility of creating compressed nuclear spin states in a room-temperature helium gas by continuous non-destructive quantum measurement, or the use of multimode entangled states with cold atoms in an optical lattice, for spatially extended field measurement or image compression.
