Experimental entanglement quantification for unknown quantum states in a semi-device-independent manner

Using the concept of non-degenerate Bell inequality, we show that quantum entanglement, the critical resource for various quantum information processing tasks, can be quantified for any unknown quantum state in a semi-device-independent manner, where the quantification is based on the experimentally obtained probability distributions and prior knowledge of the quantum dimension only. Specifically, as an application of our approach to multi-level systems, we experimentally quantify the entanglement of formation and the entanglement of distillation for qutrit-qutrit quantum systems. In addition, to demonstrate our approach for multi-partite systems, we further quantify the geometric measure of entanglement of three-qubit quantum systems. Our results supply a general way to reliably quantify entanglement in multi-level and multi-partite systems, thus paving the way to characterize many-body quantum systems by quantifying the involved entanglement.