Quantum Advantage of Ranging via Squeezed States

Quantum ranging is crucial in several applications such as radar and localization. This paper determines the quantum advantage of ranging with single-mode displaced squeezed states. Exact analytical expressions for the quantum Fisher information (QFI) about the range parameter are derived in the presence of thermal loss channels characterized by arbitrary loss and noise parameters. The quantum advantage, termed as gain, is determined as a ratio of QFI with and without employing squeezing. It is shown that the gain can be unboundedly large in the optical regime whereas it is upper bounded in the microwave regime.