Saturating a Fundamental Bound on Quantum Measurements' Accuracy

• URL: http://arxiv.org/abs/2404.12910v1
• Date: Fri, 19 Apr 2024 14:33:16 GMT
• Title: Saturating a Fundamental Bound on Quantum Measurements' Accuracy
• Authors: Nicolò Piccione, Maria Maffei, Andrew N. Jordan, Kater W. Murch, Alexia Auffèves,
• Abstract summary: We show it is possible to saturate the Wigner-Araki-Yanase theorem's upper-bound on the measurement's accuracy. We propose a simple interferometric setup in which a flying particle (the quantum meter) is used to measure the state of a qubit.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: A quantum system is usually measured through observations performed on a second quantum system, or meter, to which it is coupled. In this scenario, fundamental limitations arise as stated by the celebrated Wigner-Araki-Yanase theorem and its generalizations, predicting an upper-bound on the measurement's accuracy (Ozawa's bound). Here, we show it is possible to saturate this fundamental bound. We propose a simple interferometric setup, arguably within reach of present technology, in which a flying particle (the quantum meter) is used to measure the state of a qubit (the target system). We show that the bound can be saturated and that this happens only if the flying particle is prepared in a Gaussian wavepacket.

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