Detecting Multiparticle Entanglement of Dicke States
Bernd Lücke, J. Peise, Giuseppe Vitagliano, J. Arlt, Luis Santos, Géza Tóth, Carsten Klempt · Physical Review Letters · 2014
Recent experiments demonstrate the production of many thousands of neutral atoms entangled in their spin degrees of freedom. We present a criterion for estimating the amount of entanglement based on a measurement of the global spin. It outperforms previous criteria and applies to a wider class of entangled states, including Dicke states. Experimentally, we produce a Dicke-like state using spin dynamics in a Bose-Einstein condensate. Our criterion proves that it contains at least genuine 28-particle entanglement. We infer a generalized squeezing parameter of -11.4(5) dB.