New spin-squeezing inequalities for detecting entanglement in large ensembles of atoms outperform past approaches — especially for unpolarized states — and for symmetric states of spin-1/2 particles they are exactly equivalent to the PPT (partial-transpose) criterion; the thesis's larger aim is testing whether macroscopic systems violate classical principles like local-realism and macrorealism.

— In our words · Source: Spin Squeezing, Macrorealism and the Heisenberg uncertainty principle (Giuseppe Vitagliano)