Negativity and strong monogamy of multi-party quantum entanglement beyond qubits

Abstract

We propose the square of convex-roof extended negativity(SCREN) as a powerful candidate to characterize strong monogamy of multi-party quantum entanglement. We first provide a strong monogamy inequality of multi-party entanglement using SCREN, and show that the tangle-based multi-qubit strong monogamy inequality can be rephrased by SCREN. We further show that SCREN strong monogamy inequality is still true for the counterexamples that violate tangle-based strong monogamy inequality in higher-dimensional quantum systems rather than qubits. We also analytically show that SCREN strong monogamy inequality is true for a large class of multi-qudit states, a superposition of multi-qudit generalized W-class states and vacuums. Thus SCREN is a good alternative to characterize the strong monogamy of entanglement even in multi-qudit systems.