Abstract
One description provides only probabilities for obtaining various eigenvalues of a quantum variable. The eigenvalues and the corresponding probabilities specify the expectation value of a physical observable, which is known to be a statistical property of an ensemble of quantum systems. In contrast to this paradigm, here we demonstrate a method for measuring the expectation value of a physical variable on a single particle, namely, the polarization of a single protected photon. This realization of quantum protective measurements could find applications in the foundations of quantum mechanics and quantum-enhanced measurements.
Original language | English |
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Pages (from-to) | 1191-1194 |
Number of pages | 4 |
Journal | Nature Physics |
Volume | 13 |
Issue number | 12 |
DOIs | |
State | Published - 1 Dec 2017 |