Magnetic Field Detection Using a Two-Qubit System Under Noisy Heisenberg Interaction

TL;DR

This paper introduces a quantum magnetic field detector using a noisy two-qubit system, where the oscillation in return probability correlates with the magnetic field strength, enabling detection under noisy conditions.

Contribution

It demonstrates a method to detect magnetic fields via oscillations in return probability in a noisy two-qubit system, showing robustness against decoherence.

Findings

Oscillation frequency proportional to magnetic field strength

Decoherence does not significantly affect the detection signal

Feasibility of quantum magnetic field detection under noise

Abstract

We propose a method to design a magnetic field detector using a noisy two-qubit system. The system evolves under a noisy Heisenberg interaction Hamiltonian, and we investigate its behavior by calculating both the $l_1$-norm of quantum coherence and the return probability in the presence and absence of an external magnetic field. We allow for decoherence modeled by quasi-static charge noise in the exchange coupling of the two-qubit system and find that, while the magnetic field does not significantly influence the decoherence process, it introduces a distinct oscillation in the return probability over time. Importantly, the oscillation frequency is directly proportional to the strength of the applied magnetic field, providing a clear signature that can be used for magnetic field detection. These results point towards the feasibility of realizing a practical quantum-based magnetic field detector, with the ability to operate under noisy conditions while maintaining sensitivity to the field strength.