Pregnell KL. Measuring nonlinear functionals of quantum harmonic oscillator states.
PHYSICAL REVIEW LETTERS 2006;
96:060501. [PMID:
16605973 DOI:
10.1103/physrevlett.96.060501]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Indexed: 05/08/2023]
Abstract
Using only linear interactions and a local parity measurement we show how entanglement can be detected between two harmonic oscillators. The scheme generalizes to measure both linear and nonlinear functionals of an arbitrary oscillator state. This leads to many applications including purity tests, eigenvalue estimation, entropy, and distance measures--all without the need for nonlinear interactions or complete state reconstruction. Remarkably, experimental realization of the proposed scheme is already within the reach of current technology with linear optics.
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