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arXiv · 0705.4631

Mach-Zehnder Interferometry at the Heisenberg Limit with coherent and squeezed-vacuum light

L. Pezze'·A. Smerzi
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Abstract

We show that the phase sensitivity $Δθ$ of a Mach-Zehnder interferometer fed by a coherent state in one input port and squeezed-vacuum in the other one is i) independent from the true value of the phase shift and ii) can reach the Heisenberg limit $Δθ\sim 1/N_T$, where $N_T$ is the average number of particles of the input states. We also show that the Cramer-Rao lower bound, $Δθ\propto 1/ \sqrt{|α|^2 e^{2r} + \sinh^2r}$, can be saturated for arbitrary values of the squeezing parameter $r$ and the amplitude of the coherent mode $|α|$ by a Bayesian phase inference protocol.

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L. Pezze', A. Smerzi. 2007-05-31. Mach-Zehnder Interferometry at the Heisenberg Limit with coherent and squeezed-vacuum light. https://doi.org/10.1103/physrevlett.100.073601

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