Ultrafine Entanglement Witnessing

Abstract

Entanglement witnesses are invaluable for efficient quantum entanglement certification without the need for expensive quantum state tomography. Yet, standard entanglement witnessing requires multiple measurements and its bounds can be elusive as a result of experimental imperfections. Here we introduce and demonstrate a novel procedure for entanglement detection which seamlessly and easily improves any standard witnessing procedure by using additional available information to tighten the witnessing bounds. Moreover, by relaxing the requirements on the witness operators, our method removes the general need for the difficult task of witness decomposition into local observables. We experimentally demonstrate entanglement detection with our approach using a separable test operator and a simple fixed measurement-device for each agent. Finally we show that the method can be generalized to higher-dimensional and multipartite cases with a complexity that scales linearly with the number of parties.

5 pages + 3 pages supplemental material, 4 figures

References in corpus (3)

• Detecting Genuine Multipartite Entanglement with Two Local Measurements
• Full multipartite entanglement of frequency comb Gaussian states
• Necessary and sufficient conditions for bipartite entanglement

Cited by in corpus (7)

• Design and Experimental Performance of Local Entanglement Witness Operators
• Quantitative Coherence Witness for Finite Dimensional States
• Verifying bound entanglement of dephased Werner states
• Separable and Inseparable Quantum Trajectories
• Displaced photon-number entanglement tests
• A hierarchy of entanglement criteria for four qubit symmetric Greenberger-Horne-Zeilinger diagonal states
• Confident entanglement detection via separable numerical range