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 $\alpha\geq2$, and the $\alpha$-th power of the entanglement of formation for all $\alpha\geq\sqrt{2}$. These monogamy relations are shown to be tighter than the existing ones.