
The nonlocal correlations that exist in quantum physics can be used in a sensor network to improve the sensitivity of the measurement of an extended field or some of its spatial features. Taking an atomic ensemble in a spin squeezed state distributed in different spatial modes (the sensors) as a resource, I will show what kind of gain can be obtained in two different cases. First, assuming that local manipulations can be made on the sensors but all measurements are collective, and second, assuming that both local manipulations and local measurements are possible on each sensor. Generalizing to the case of a large number of sensors, we show applications to imaging and compressed sensing.
