No abstract

No abstract

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. PACS:O3.67.Hk, 03.65.Ud, 03.67.Mn Entanglement is considered to be the central resource for quantum information and computation [1,2], and numerous theoretical and experimental detailed works have been done in this field [3][4][5][6]. As an important feature in the quantum many-body system, the multi-particle entanglement has been intensively investigated since it is significantly different from the trivial extension of biparticle entanglement [7][8][9][10], and the characterization and classification of such entanglement now become a issue full of interest [11,12]. A common feature of entanglement for multipartite quantum system is that its non-local properties do not change under local transformations, so local unitary (LU) transformations invariants has been used for the classification of the multi-qubit states [13,14].As perfect entanglement resource in quantum communication and computing, the maximally multi-qubit entangled state (MMES) have received much theoretical attentions. A definition of MMES has been proposed recently, yet the numerical searching method base on this definition can

No abstract

No abstract