Quantum Measurement Bounds beyond the Uncertainty Relations

被引:50
|
作者
Giovannetti, Vittorio [1 ,2 ]
Lloyd, Seth [3 ]
Maccone, Lorenzo [4 ]
机构
[1] Scuola Normale Super Pisa, NEST, I-56126 Pisa, Italy
[2] CNR, Ist Nanosci, I-56126 Pisa, Italy
[3] MIT, Dept Mech Engn, Cambridge, MA 02139 USA
[4] Univ Pavia, Dipartimento Fis Alessandro Volta, Ist Nazl Fis Nucl, Sez Pavia, I-27100 Pavia, Italy
基金
美国国家科学基金会;
关键词
PRECISION PHASE MEASUREMENT; STATES; LIMIT;
D O I
10.1103/PhysRevLett.108.260405
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
In quantum mechanics, the Heisenberg uncertainty relations and the Cramer-Rao inequalities typically limit the precision in the estimation of a parameter through the standard deviation of a conjugate observable. Here we extend these relations by giving a bound to the precision of a parameter in terms of the expectation value of the conjugate observable. This has both foundational and practical consequences: in quantum optics it resolves a controversy over which is the ultimate precision in interferometry.
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页数:4
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