Bright six-partite continuous variable entanglement using cascaded   four-wave mixing processes in a four-level atomic system
  We theoretically show that bright six-partite continuous-variable entanglement can be generated using cascaded four-wave mixing effects of third-order nonlinearity atomic systems above threshold. The six-partite continuous-variable entanglement among the six cavity fields with different frequencies is analyzed by applying optimized inseparability criteria proposed by Van Loock and Furusawa. 
Guangqiang He, Xufei Wu and Yi Gu
quant-ph