Catability as a metric for evaluating superposed coherent states

TL;DR

This paper introduces a new, practical criterion based on nonlinear squeezing for detecting cat-like features in superposed coherent states, improving robustness and efficiency over traditional fidelity-based methods.

Contribution

The authors propose a directly measurable, noise-robust criterion for identifying superposed coherent states that does not require full quantum state tomography.

Findings

The criterion effectively detects cat-like features even under loss and noise.

Numerical simulations confirm the method's robustness and potential for experimental use.

The approach generalizes to complex superpositions like multiheaded cat states.

Abstract

Superposed coherent states are central to quantum technologies, yet their reliable identification remains a challenge, especially in noisy or resource-constrained settings. We introduce a novel, directly measurable criterion for detecting cat-like features in quantum states, rooted in the concept of nonlinear squeezing. This approach bypasses the need for full state tomography and reveals structure where fidelity fails. The numerical results confirm its robustness under loss and its potential for experimental implementation. The method naturally generalizes to more exotic superpositions, including multiheaded cat states.