In some physical systems, like light or atoms, one or more components can be squeezed. In light for example a component can be squeezed, providing for a reduction of quantum noise in that component, to which it corresponds the antisqueezing of the other. Other systems, like atomic ensembles, can be squeezed simultaneously in two components, providing a powerful tool to reduce quantum noise in these. Here theoretical features of macroscopic spin systems with two squeezed components will be explored. This study suggests that this atomic systems could contribute to increase the current sensitivity in magnetometry. We perform an experiment to get a polarized state in 87Rb atomic system squeezed in two components by QND measurements and the rotation of the spin vector by an external magnetic eld. Our proposal in obtaining an atomic squeezed state in two components can dramatically increase the sensitivity of magnetometers, very important for tests of fundamental physics as well for technological applications.

Giorgio Colangelo

giorgio.colangelo@icfo.es