An entanglement measure for multipartite pure states is formulated using the product of the von Neumann entropy of the reduced density matrices of the constituents. Based on this new measure, all possible ways of the maximal entanglement of the triqubit pure states are studied in detail and all types of the maximal entanglement have been compared with the result of ‘the average entropy’. The new measure can be used to calculate the degree of entanglement, and an improvement is given in the area near the zero entropy.
CAO Wancang1,2, LIU Dan2, PAN Feng3 & LONG Guilu2,4 1. Department of Physics, Chifeng College, Chifeng 024001, China