Generalized Criterion of Maximally Multi-Qubit Entanglement
  We first present a generalized criterion for maximally entangled states of 2, 3, 4, 5, 6, 8 and in theory to arbitrary-number qubits. By this criterion, some known highly entangled multi-qubit states are examined and a new genuine eight-qubit maximally entangle state is obtained. For the 4, 7 and 8 qubits system in which no maximally multi-qubit entangled states (MMES) is thought to exist before, we find that the proved and most suspected MMESes, are not completely mixed in subsystem with a critical-number qubits, below which the subsystems are all completely mixed. We believe that the new criterion and MMES can play important role in quantum information technology, such as the teleportation and dense coding. 
Xinwei Zha, Chenzhi Yuan, and Yanpeng Zhang
quant-ph