Rare-Event Quantum Sensing using Logical Qubits

TL;DR

This paper introduces a quantum error correction-based protocol for detecting rare signals amidst noise, leveraging higher-order correlations and non-linear syndrome processing to enhance sensitivity.

Contribution

It proposes a novel quantum sensing scheme that uses logical qubits and QEC to improve detection of rare events, extending coherence time and discriminating signals from noise.

Findings

Enhanced sensitivity to rare signals demonstrated

QEC extends logical coherence time

Improved detection performance over traditional methods

Abstract

We present a novel protocol to detect rare signals in a noisy environment using quantum error correction (QEC). The key feature of our protocol is the discrimination between signal and noise through distinct higher-order correlations, realized by the non-linear processing that occurs during syndrome extraction in QEC. In this scheme, QEC has two effects: First, it sacrifices part of the signal $\epsilon$ by recording a reduced, stochastic, logical phase $\phi_L = \mathcal{O}(\epsilon^3)$. Second, it corrects the physical noise and extends the (logical) coherence time for signal acquisition. For rare signals occurring at random times in the presence of local Markovian noise, we explicitly demonstrate an improved sensitivity of our approach over more conventional sensing strategies.