Tighter entanglement monogamy relations of qubit systems

Monogamy relations characterize the distributions of entanglement in multipartite systems. We investigate monogamy relations related to the concurrence C and the entanglement of formation E. We present new entanglement monogamy relations satisfied by the alpha-th power of concurrence for all alpha >= 2, and the alpha-th power of the entanglement of formation for all alpha > root 2. These monogamy relations are shown to be tighter than the existing ones.