Discrete photon statistics from continuous microwave measurements

TL;DR

This paper introduces a method to derive discrete photon statistics from continuous microwave measurements by utilizing cumulants, enabling characterization of quantum fields with very low photon numbers.

Contribution

The authors present a novel approach to extract discrete photon statistics from continuous quadrature measurements using cumulants, improving analysis of microwave quantum signals.

Findings

Successfully recover up to the third moment of photon statistics

Extract useful data from up to the sixth cumulant of continuous measurements

Enable characterization of signals with less than one photon on average

Abstract

Photocount statistics are an important tool for the characterization of electromagnetic fields, especially for fields with an irrelevant phase. In the microwave domain, continuous rather than discrete measurements are the norm. Using a novel approach, we recover discrete photon statistics from the cumulants of a continuous distribution of field quadrature measurements. The use of cumulants allows the separation between the signal of interest and experimental noise. Using a parametric amplifier as the first stage of the amplification chain, we extract useful data from up to the sixth cumulant of the continuous distribution of a coherent field, hence recovering up to the third moment of the discrete statistics associated with a signal with much less than one average photon.