1205.3048 (Florian Fröwis et al.)

Measures of macroscopicity for quantum spin systems    [PDF]

Florian Fröwis, Wolfgang Dür

We investigate the notion of "macroscopicity" in the case of large quantum spin systems and provide two main results. First, we motivate the Fisher information as a measure for the macroscopicity of quantum states. Second, we compare the existing literature of this topic. We report on a hierarchy among the measures and we conclude that one should carefully distinguish between "macroscopic quantum states" and "macroscopic superpositions", which is a strict subclass of the former.

View original: http://arxiv.org/abs/1205.3048