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 ge 2), and the (alpha )-th power of the entanglement of formation for all (alpha ge sqrt{2}). These monogamy relations are shown to be tighter than the existing ones.