Optimized Detection of High-Dimensional Entanglement

Abstract

Entanglement detection is one of the most conventional tasks in quantum information processing. While most experimental demonstrations of high-dimensional entanglement rely on fidelity-based witnesses, these are powerless to detect entanglement within a large class of entangled quantum states, the so-called unfaithful states. In this paper, we introduce a highly flexible automated method to construct optimal tests for entanglement detection given a bipartite target state of arbitrary dimension, faithful or unfaithful, and a set of local measurement operators. By restricting the number or complexity of the considered measurement settings, our method outputs the most convenient protocol to test the entanglement of the target state in the lab. Using the 3-setting protocols generated by our method, we experimentally certify 2-and 3-dimensional entanglement in 4-dimensional unfaithful states. I. INTRODUCTIONEntanglement is the bedrock of most quantum information processing protocols (Gühne and Tóth, 2009; Horodecki et al., 2009). It is a key resource in quantum teleportation (Bennett et al., 1993), entanglement-based quantum key distribution (QKD) (Yin et al., 2017) and quantum communication complexity (Buhrman et al., 2010). Generating high-quality entangled states and detecting them reliably is a crucial prerequisite to conduct any quantum communication task.

Suppressing the degeneration of quantum resources through coupling auxiliary qubits

“…Zhang et al explored the multipartite entanglement in an optical lattice [8]. Hu et al realized the optimal detection of highdimensional entanglement, and their method is applicable to bipartite state of arbitrary dimension [9]. The genuinely multipartite entanglement with general and Robust device-independent were verified by Zhang et al [10].…”

Non-unital channel can sometimes enhance faithfulness of two-qubit entanglement

“…As the faithful sates are equivalent to the states with f > 1/d, faithfulness of entanglement can be enhanced by this class of channel. Recently, faithfulness of entanglement was studied by experiments [7,20]. The authors demonstrated a situation in which an unfaithful state is brought to a faithful one in the amplitude damping channel [7].…”