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arXiv · 1703.03651

Enhancing interferometric sensitivity by non-classical light from quantum non-demolition measurements in cavity QED

K. Gietka·T. Wasak·J. Chwedenczuk·F. Piazza·H. Ritsch
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Abstract

We propose an enhanced optical interferometer based on tailored non-classical light generated by nonlinear dynamics and projective measurements in a three-level atom cavity QED system. A coherent state in the cavity becomes dynamically entangled with two ground states of the atom and is transformed to a macroscopic superposition state via a projective measurement on the atom. We show that the resulting highly non-classical state can improve interferometric precision measurements well beyond the shot-noise limit once combined with a classical laser pulse at the input of a Mach-Zehnder interferometer. For a practical implementation, we identify an efficient phase shift estimation scheme based on the counting of photons at the interferometer output. Photon losses and photon-counting errors deteriorate the interferometer sensitivity, but we demonstrate that it still can be significantly better than the shot-noise limit under realistic conditions.

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K. Gietka, T. Wasak, J. Chwedenczuk, F. Piazza, H. Ritsch. 2017-09-05. Enhancing interferometric sensitivity by non-classical light from quantum non-demolition measurements in cavity QED. https://doi.org/10.1140/epjd%2Fe2017-80235-2

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