Parity measurement of remote qubits using dispersive coupling and photodetection

TL;DR

This paper introduces a deterministic, non-destructive protocol for measuring the parity of two remote qubits using dispersive coupling to resonators and photodetection, advancing quantum error correction methods.

Contribution

It presents a novel protocol for remote parity measurement that works with time-independent dispersive coupling and number-resolving photodetectors, unlike previous methods.

Findings

Protocol is deterministic with no fundamental success probability bound

Works with time-independent dispersive coupling and number-resolving photodetectors

Enables non-destructive parity measurement of remote qubits

Abstract

Parity measurement is a key step in many entanglement generation and quantum error correction schemes. We propose a protocol for non-destructive parity measurement of two remote qubits, i.e., macroscopically separated qubits with no direct interaction. The qubits are instead dispersively coupled to separate resonators that radiate to shared photodetectors. The scheme is deterministic in the sense that there is no fundamental bound on the success probability. Compared to previous proposals, our protocol addresses the scenario where number resolving photodetectors are available but the qubit-resonator coupling is time-independent and only dispersive.