Qutrit state discrimination with mid-circuit measurements

TL;DR

This paper introduces a mid-circuit measurement technique for qutrit state discrimination that leverages existing qubit readout methods, offering comparable performance to traditional IQ discriminators and facilitating standard quantum benchmarking.

Contribution

The study presents a novel qutrit discrimination method using mid-circuit measurements based on binary qubit readout, improving scalability and compatibility with standard quantum processors.

Findings

Comparable performance to IQ discriminators

Compatible with standard qubit calibration

Enables typical benchmarking experiments

Abstract

Qutrit state readout is an important technology not only for execution of qutrit algorithms but also for erasure detection in error correction circuits and leakage error characterization of the gate set. Conventional technique using a specialized IQ discriminator requires memory intensive IQ data for input, and has difficulty in scaling up the system size. In this study, we propose the mid-circuit measurement based discrimination technique which exploits a binary discriminator for qubit readout. Our discriminator shows comparable performance with the IQ discriminator, and readily available for standard quantum processors calibrated for qubit control. We also demonstrate our technique can reimplement typical benchmarking and characterization experiments such as leakage randomized benchmarking and state population decay measurement.