The effect of Quantum Statistics on the sensitivity in an SU(1,1) interferometer

TL;DR

This paper investigates how the quantum statistics of Schrödinger cat states influence phase sensitivity in an SU(1,1) interferometer, revealing optimal conditions and robustness to losses, with implications for quantum metrology.

Contribution

It provides a theoretical analysis of the impact of quantum statistics of cat states on phase sensitivity in SU(1,1) interferometers, highlighting optimal input states and loss resilience.

Findings

Optimal sensitivity at relative phase π with odd coherent states

Schrödinger cat states are more loss-resistant than squeezed vacuum states

Quantum enhancement decreases as cat state amplitude increases

Abstract

We theoretically study the effect of quantum statistics of the light field on the quantum enhancement of parameter estimation based on cat state input the SU(1,1) interferometer. The phase sensitivity is dependent on the relative phase $\theta$ between two coherent states of Schr\"{o}dinger cat states. The optimal sensitivity is achieved when the relative phase is $\pi$% , i.e., odd coherent states input. For a coherent state input into one port, the phase sensitivity of the odd coherent state into the second input port is inferior to that of the squeezed vacuum state input. However, in the presence of losses the Schr\"{o}dinger cat states are more resistant to loss than squeezed vacuum states. As the amplitude of Schr\"{o}dinger cat states increases, the quantum enhancement of phase sensitivity decreases, which shows that the quantum statistics of Schr\"{o}dinger cat states tends towards Poisson statistics from sub-Poisson statistics or super-Poisson statistics.