Quantum measurement

Quantum measurement is the process of extracting information from a quantum system, typically described by operators acting on a Hilbert space. The most general framework uses Positive Operator-Valued Measures (POVMs), which extend beyond projective (sharp) measurements to include all possible quantum measurements. Unsharp measurements are a type of POVM that provides partial, noisy, or coarse-grained information about a system without fully collapsing its state, allowing a trade-off between information gain and disturbance. We have significantly contributed to the study of quantum measurements, particularly in developing and experimentally implementing generalized measurements such as POVMs and unsharp measurements. Our work has demonstrated how unsharp measurements can be realized in photonic systems, enabling fundamental tests of quantum mechanics like contextuality and nonlocality. We have also applied these concepts to quantum information tasks, showing how generalized measurements enhance protocols in quantum communication and quantum state discrimination.

• How to avoid (apparent) signaling in Bell tests, M. Smania, M. Kleinmann, A. Cabello, M. Bourennane, Quantum 9, 1760 (2025)
• Generalized measurements on qubits in quantum randomness certification and expansion, P. Mironowicz, M. Grünfeld, M. Bourennane, Physical Review Applied 22 (4), 044041 (2024)
• Exponentially decreasing critical detection efficiency for any Bell inequality, N. Miklin, A. Chaturvedi, M. Bourennane, M. Pawłowski, A. Cabello, Physical Review Letters 129 (23), 230403 (2022)
• Noise-robust preparation contextuality shared between any number of observers via unsharp measurements, H. Anwer, N. Wilson, R. Silva, S. Muhammad, A. Tavakoli, M. Bourennane, Quantum 5, 551 (2021)
• Experimental characterization of unsharp qubit observables and sequential measurement incompatibility via quantum random access codes, H. Anwer, S. Muhammad, W. Cherifi, N. Miklin, A. Tavakoli, M. Bourennane, Physical Review Letters 125 (8), 080403 (2020)
• Self-testing nonprojective quantum measurements in prepare-and-measure experiments, A. Tavakoli, M. Smania, T. Vértesi, N. Brunner, M. Bourennane, Science Advances 6 (16), eaaw6664 (2020)
• Experimental certification of an informationally complete quantum measurement in a device-independent protocol, M. Smania, P. Mironowicz, M. Nawareg, M. Pawłowski, A. Cabello, M. Bourennane, Optica 7 (2), 123-128 (2020)
• Experimental test of maximal tripartite nonlocality using an entangled state and local measurements that are maximally incompatible, H. Anwer, M. Nawareg, A. Cabello, M. Bourennane, Physical Review A 100 (2), 022104 (2019)
• Steering is an essential feature of non-locality in quantum theory, R. Ramanathan, D. Goyeneche, S. Muhammad, P. Mironowicz, M. Grünfeld, M. Bourennane, Nature Communications 9 (1), 4244 (2018)
• Experimental device-independent certification of a symmetric, informationally complete, positive operator-valued measure, M. Smania, P. Mironowicz, M. Nawareg, M. Pawlowski, A. Cabello, M. Bourennane, Quantum 3, 6.928 (2018)
• Experimental tests of classical and quantum dimensionality, J. Ahrens, P. Badziąg, M. Pawłowski, M. Żukowski, M. Bourennane, Physical Review Letters 112 (14), 140401 (2014)
• Bounding quantum theory with the exclusivity principle in a two-city experiment, M. Nawareg, F. Bisesto, V. D'Ambrosio, E. Amselem, F. Sciarrino, M. Bourennane, A. Cabello, arXiv preprint arXiv:1311.3495 (2013)