Gaussian interferometric power

Adesso, Gerardo

Abstract

The interferometric power of a bipartite quantum state quantifies the precision, measured by quantum Fisher information, that such a state enables for the estimation of a parameter embedded in a unitary dynamics applied to one subsystem only, in the worst-case scenario where a full knowledge of the generator of the dynamics is not available a priori. For finite-dimensional systems, this quantity was proven to be a faithful measure of quantum correlations beyond entanglement. Here we extend the notion of interferometric power to the technologically relevant setting of optical interferometry with continuous-variable probes. By restricting to Gaussian local dynamics, we obtain a closed formula for the interferometric power of all two-mode Gaussian states. We identify separable and entangled Gaussian states which maximize the interferometric power at fixed mean photon number of the probes and discuss the associated metrological scaling. At fixed entanglement of the probes, highly thermalized states can guarantee considerably larger precision than pure two-mode squeezed states.

Citation

Adesso, G. (2014). Gaussian interferometric power. Physical Review A, 90(2), https://doi.org/10.1103/PhysRevA.90.022321

• Journal Article Type: Article
• Acceptance Date: Jun 20, 2014
• Online Publication Date: Aug 20, 2014
• Publication Date: Aug 20, 2014
• Deposit Date: Oct 11, 2017
• Publicly Available Date: Oct 11, 2017
• Journal: Physical Review A
• Print ISSN: 2469-9926
• Electronic ISSN: 2469-9934
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 90
• Issue: 2
• DOI: https://doi.org/10.1103/PhysRevA.90.022321
• Public URL: https://nottingham-repository.worktribe.com/output/734005
• Publisher URL: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.90.022321
• Additional Information: ©2014 American Physical Society
• Contract Date: Oct 11, 2017