Spin Amplification with Inhomogeneous Broadening

TL;DR

The paper introduces a robust spin amplification method using ancillary qubits that effectively amplifies a target qubit's state even with inhomogeneous broadening, aiding in single-spin readout.

Contribution

It proposes a novel spin amplification scheme resilient to inhomogeneous broadening, enabling reliable single-spin measurement.

Findings

Amplification remains effective despite inhomogeneous coupling and frequency variations.

The scheme achieves fast and accurate spin state amplification.

Robustness against realistic imperfections enhances practical applicability.

Abstract

A long-lived qubit is usually well-isolated from all other systems and the environments, and so is not easy to couple with measurement apparatus. It is sometimes difficult to implement reliable projective measurements on such a qubit. One potential solution is spin amplification with many ancillary qubits. Here, we propose a spin amplification technique, where the ancillary qubits state change depending on the state of the target qubit. The technique works even in the presence of inhomogeneous broadening. We show that fast and accurate amplification is possible even if the coupling and frequency of the ancillary qubits is inhomogeneous. Since our scheme is robust against realistic imperfections, this could provide a new mechanism for reading out a single spin that could not have been measured using the previous approaches.