Generalized Modular Value with Nonclassical Pointer States

TL;DR

This paper explores how non-classical pointer states, such as squeezed and Schrödinger cat states, enhance the precision and negativity in generalized modular value quantum measurements compared to semi-classical states.

Contribution

It introduces the use of non-classical pointer states in the modular value scheme and analyzes their advantages over semi-classical states in quantum measurement precision.

Findings

Non-classical pointer states increase measurement precision.

Non-classical states enhance negativity of the field.

Quantum measurement sensitivity is improved with non-classical pointers.

Abstract

In this study, we investigate the advantages of non-classical pointer states in the generalized modular value scheme. We consider a typical von Neumann measurement with a discrete quantum pointer, where the pointer is a projection operator onto one of the states of the basis of the pointer Hilbert space. We separately calculate the conditional probabilities, Q_{M} factors, and signal-to-noise ratios of quadrature operators of coherent, coherent squeezed, and Schr\"odinger cat pointer states and find that the non-classical pointer states can increase the negativity of the field and precision of measurement compared with semi-classical states in generalized measurement problems characterized by the modular value.