Improving quantum precision using quantum parametric amplification

Wenchao Ge, Brian C. Sawyer, J. Britton +3 more

Joseph W. Haus, Anup R. Pandey, Peter Powers

Zhiyuan Wang, Zijing Zhang, Yuan Zhe Zhao

The precision measurement of Doppler frequency shifts is of great significance for improving the precision of speed measurement. This paper proposes a precision measurement scheme of tiny Doppler shifts by a parametric amplification process and squeezed vacuum state. This scheme takes a parametric amplification process and squeezed vacuum state into a detection system, so that the measurement precision of tiny Doppler shifts can exceed the Cramér–Rao bound of coherent light. Simultaneously, a simulation study is carried out on the theoretical basis, and the following results are obtained: for the signal light of Gaussian mode, when the amplification factor g = 1 and the squeezed factor r = 0.5, the measurement error of Doppler frequency shifts is 14.4% of the Cramér–Rao bound of the coherent light in our system. At the same time, when the local light mode and squeezed vacuum state mode are optimized, the measurement precision of this scheme can be further improved by ( 2 n + 1 ) / ( n + 1 ) times, where n is the mode-order of the signal light.

Xiaojie Zuo, Zhihui Yan, Yanni Feng +4 more

High precision interferometers are the building blocks of precision metrology and the ultimate interferometric sensitivity is limited by the quantum noise. Here, we propose and experimentally demonstrate a compact quantum interferometer involving two optical parametric amplifiers and the squeezed states generated within the interferometer are directly used for the phase-sensing quantum state. By both squeezing shot noise and amplifying phase-sensing intensity the sensitivity improvement of 4.86±0.24 dB beyond the standard quantum limit is deterministically realized and a minimum detectable phase smaller than that of all present interferometers under the same phase-sensing intensity is achieved. This interferometric system has significantly potential applications in a variety of measurements for tiny variances of physical quantities.

Michael Renger, Stefan Pogorzalek, Qiming Chen +6 more

B. Schr�der