title: Optimal spin squeezing inequalities detect bound entanglement in spin models.
abstract: We determine the complete set of generalized spin squeezing inequalities. These are entanglement criteria that can be used for the experimental detection of entanglement in a system of spin-1/2 particles in which the spins cannot be individually addressed. They can also be used to show the presence of bound entanglement in the thermal states of several spin models.
authors.affiliation: ICFO-Institut de Ciències Fotòniques, E-08860 Castelldefels (Barcelona), Spain.
authors.forename: Géza
authors.initials: G
authors.lastname: Tóth
authors.forename: Christian
authors.initials: C
authors.lastname: Knapp
authors.forename: Otfried
authors.initials: O
authors.lastname: Gühne
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Briegel