Spin squeezing as a measure of entanglement in a two-qubit system
Spin squeezing as a measure of entanglement in a two-qubit system
We show that the two definitions of spin squeezing extensively used in the literature [M. Kitagawa and M. Ueda, Phys. Rev. A 47, 5138 (1993) and D.J. Wineland et al., Phys. Rev. A 50, 67 (1994)] give different predictions of entanglement in the two-atom Dicke system. We analyze differences between …