# Quantifying nonclassicality by characteristic functions

## TL;DR

This paper introduces a method to quantify the nonclassicality of quantum states using characteristic functions, providing criteria to estimate nonclassicality degrees through phase-space analysis, with applications to squeezed states.

## Contribution

It presents new criteria based on characteristic functions to measure nonclassicality, linking it to quantum superpositions and demonstrating practical estimation methods.

## Key findings

- Criteria successfully applied to squeezed states
- Effective estimation of nonclassicality degree
- Insights into quantum superpositions and classical mixing

## Abstract

In this paper, we use the characteristic function, i.e., the Fourier transform of the Glauber-Sudarshan phase-space distribution, to find the degree of nonclassicality of a given state. This degree of nonclassicality quantifies the nonclassicality in terms of quantum superpositions. We demonstrate two ways to determine or to estimate the degree of nonclassicality by studying the properties of the characteristic functions. The developed criteria are applied to two examples of squeezed states undergoing a classical mixing or a nonclassical superposition with vacuum.