Quantum sensing with tunable superconducting qubits: optimization and speed-up

TL;DR

This paper demonstrates optimized quantum magnetic flux sensing using tunable superconducting qubits, achieving high accuracy and faster measurement speeds through entangled states and phase estimation algorithms.

Contribution

It introduces a method to optimize quantum flux sensing with tunable transmon qubits, comparing entangled and single-qubit states for improved accuracy and speed.

Findings

Flux sensing accuracy reaches 10^{-8} Φ_0

Entangled states outperform single qubits in sensing

Sensing speed scales as 1/t, indicating speed-up

Abstract

Sensing and metrology play an important role in fundamental science and applications by fulfilling the ever-present need for more precise data sets and by allowing researchers to make more reliable conclusions on the validity of theoretical models. Sensors are ubiquitous. They are used in applications across a diverse range of fields including gravity imaging, geology, navigation, security, timekeeping, spectroscopy, chemistry, magnetometry, healthcare, and medicine. Current progress in quantum technologies has inevitably triggered the exploration of the use of quantum systems as sensors with new and improved capabilities. This article describes the optimization of the quantum-enhanced sensing of external magnetic fluxes with a Kitaev phase estimation algorithm based on a sensor with tunable transmon qubits. It provides the optimal flux biasing point for sensors with different maximal qubit transition frequencies. An estimation of decoherence rates is made for a given design. The use of $2-$ and $3-$qubit entangled states for sensing are compared in simulation with the single qubit case. The flux sensing accuracy reaches $10^{-8}\cdot\Phi_0$ and scales with time as $\sim\ 1/t$ which proves the speed-up of sensing with high ultimate accuracy.