Quantifying Nonclassicality of su(1, 1) Squeezed States by Quantum Fisher Information

Abstract

Evaluating quantum Fisher information is an essential task in the parameter estimation and quantum metrology. It quantifies the sensitivity of a quantum state to probe and capture variations in an unknown parameter, which is aimed to be estimated. In this context, the amount of quantum Fisher information measures the operational nonclassicality of a given state, regarded as a quantifiable resource for quantum metrology. We construct su(1, 1) coherent states, using the Perelomov formalism, and present their various optical realizations forming a general class of su(1, 1) algebraic squeezed states. We analyze the nonclassicality of these states and evaluate the corresponding Fisher information. Also, we find that su(1, 1) algebraic squeezed states surpass the standard quantum limit, thereby exhibiting a quantum metrological advantage.