Berlin 2014 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 64: Quantum information: Concepts and methods V

Q 64.5: Talk

Friday, March 21, 2014, 15:00–15:15, Kinosaal

The necessity of entanglement for improved phase sensitivity — •Simon Laibacher und Matthias Freyberger — Institut für Quantenphysik, Universität Ulm, D-89069 Ulm, Germany

It is well known that the exploitation of non-classical properties of light in optical interferometry allows for a phase sensitivity that surpasses the classical limit [1,2]. Most of the approaches apply entangled states of light [3]. However, in quantum optics this is, in contrast to atom interferometry, not the only way to introduce non-classical correlations and indeed not necessary to improve phase sensitivity [4]. We present an interferometric measurement scheme based on homodyne detection which allows us to easily determine the influence of the presence or absence of entanglement in otherwise identical states on phase sensitivity. As we show, in both cases basically the same scaling of the phase uncertainty can be achieved.

[1] C. M. Caves, Phys. Rev. D 23, 1693 (1981).

[2] V. Giovanetti et al., Nature Photon. 5, 222 (2011).

[3] C. C. Gerry and J. Mimih, Contemp. Phys. 51, 497 (2010).

[4] P. M. Anisimov et al., Phys. Rev. Lett. 104, 103602 (2010).