Invariance of the Multi-Mode Nonclassical Measure of Nonclassical Light

Young‐Chul Kim, Kisik Kim, Dae-Yoon Park

Vladimir I. Man’ko

Vladimir I. Man’ko

Kisik Kim

We generate multi-mode nonclassical correlations in the output field from the single-mode nonclassicality in the input field with a unitary optical device. It is shown that, according to the invariance of nonclassicality, the decrement of the single-mode nonclassicality is compensated for by the appearance of multi-mode nonclassical correlations. We demonstrate a complete transfer of single-mode nonclassicality to a multi-mode nonclassical correlation for a 1 × 2 array of beam splitters, when chaotic lights are taken as auxiliary classical fields of the input.

Wenchao Ge, Kurt A. Jacobs, Muhammad Suhail Zubairy

Abstract It is well-known that the precision of a phase measurement with a Mach-Zehnder interferometer employing strong classic light can be greatly enhanced with the addition of weak nonclassical light. In the context of quantifying nonclassicality, the amount by which a nonclassical state can enhance precision in this way has been termed its ’metrological power’. To-date, the enhancement provided by weak nonclassical states has been calculated only for specific measurement configurations. Here we are able to optimize over all measurement configurations to obtain the maximum enhancement that can be achieved by any single or multi-mode nonclassical state together with strong classical states, for local and distributed quantum metrology employing any linear or nonlinear single-mode unitary transformation. Our analysis reveals that the quantum Fisher information for quadrature-displacement sensing is the sole property that determines the maximum achievable enhancement in all of these different scenarios, providing a unified quantification of the metrological power.

I. N. Agafonov, Maria V. Chekhova, Olga Aleksandrovna Ivanova +1 more

We demonstrate a technique of measuring Glauberpsilas normalized correlation functions for nonclassical light generated in the pulsed regime. In particular, intensity correlation functions are studied for the transition between spontaneous and stimulated parametric down-conversion.