Operational Resource Theory of Nonclassicality and the Mach-Zehnder Interferometer
Wenchao Ge, Kurt A. Jacobs, Saeed Asiri, Michael Foss‐Feig, Muhammad Suhail Zubairy · arXiv (Cornell University) · 2019
The nonclassical properties of quantum states are of tremendous interest due to their potential applications in future technologies. It has recently been realized that the concept of a theory is a powerful approach to quantifying and understanding nonclassicality. An important goal in this endeavor is to find resource theoretic measures of nonclassicality that are operational, meaning that they also quantify the ability of quantum states to provide enhanced performance for specific tasks, such as precision sensing. Here we present such a measure: it satisfies the necessary requirements of a resource-theoretic measure, and has the closest possible relationship to precision measurement: it quantifies the quantum-enhanced precision for pure states and is a tight upper bound on this precision for mixed states. We also show that a balanced Mach-Zehnder Interferometer provides a way to experimentally extract this measure, and we examine how the measure quantifies the concept of macroscopicity.