Practical and Efficient Verification of Entanglement with Incomplete Measurement Settings

  • Event Date: 2025-12-17
  • Quantum information and communication
  • Speaker: Prof. Joonwoo Bae ( School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), South Korea)  /  Host: Prof. Huan-Yu Ku (Dept. of Physics, NTNU)
    Place: F104, Gongguan Campus, NTNU

Time:11:00, Wednesday, December 17, 2025
Speaker:Prof. Joonwoo Bae
              School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), South Korea
Title: Practical and Efficient Verification of Entanglement with Incomplete Measurement Settings
Place : F104, Gongguan Campus, NTNU

Abstract:
A measurement setting for quantum state identification, namely tomographically complete measurements, can verify all properties of quantum states; once a state is verified, one can determine its properties, such as entanglement, purity, fidelity, correlation functions, etc. A fraction of the measurement results, yet insufficient to verify a state, may reveal specific properties of a state. In this work, we establish a practical, efficient framework for verifying entangled states when a measurement setting is provided. We construct observables, called entanglement witnesses (EWs), that can distinguish entangled states from separable ones from tomographically incomplete measurements. We show that estimating a few Pauli observables can construct many EWs. We also present a proof-of-principle demonstration of detecting entangled states with photon-polarization qubits. Our results find the maximal usefulness of an incomplete measurement setting for detecting entangled states.

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