# Identification of nonclassical properties of light with multiplexing layouts

## TL;DR

This paper extends a detector-independent method to identify nonclassical light properties using multiplexing layouts, deriving a general theory and applying it to experimental data with superconducting sensors to reveal new nonclassicality criteria.

## Contribution

It introduces a comprehensive theoretical framework for nonclassicality detection in multiplexed setups and demonstrates its effectiveness on experimental data, including the novel concept of sub-multinomial light.

## Key findings

- Sub-multinomial light outperforms sub-Poisson and sub-binomial criteria
- The theory applies to arbitrary detectors and multiplexing configurations
- Experimental data confirms the validity of the new nonclassicality criteria

## Abstract

In a recent contribution, we introduced and applied a detector-independent method to uncover nonclassicality. Here, we extend those techniques and give more details on the performed analysis. We derive a general theory of the positive-operator-valued measure that describes multiplexing layouts with arbitrary detectors. From the resulting quantum version of a multinomial statistics, we infer nonclassicality probes based on a matrix of normally ordered moments. We discuss these criteria and apply the theory to our data which are measured with superconducting transition-edge sensors. Our experiment produces heralded multi-photon states from a parametric down-conversion light source. We show that the known notions of sub-Poisson and sub-binomial light can be deduced from our general approach, and we establish the concept of sub-multinomial light, which is shown to outperform the former two concepts of nonclassicality for our data.