Fourier Transform Noise Spectroscopy

TL;DR

This paper introduces a simplified noise spectroscopy method for quantum systems that uses Fourier transforms of free induction decay or spin echo measurements, reducing experimental complexity while accurately characterizing noise spectra.

Contribution

The authors present a novel Fourier transform-based noise spectroscopy technique that eliminates the need for extensive pulse sequences, improving efficiency and applicability in quantum device characterization.

Findings

Accurately recovers noise spectra including 1/f noise

Outperforms previous dynamical decoupling schemes

Demonstrates robustness against measurement errors

Abstract

Spectral characterization of noise environments that lead to the decoherence of qubits is critical to developing robust quantum technologies. While dynamical decoupling offers one of the most successful approaches to characterize noise spectra, it necessitates applying large sequences of $\pi$ pulses that increase the complexity and cost of the method. Here, we introduce a noise spectroscopy method that utilizes only the Fourier transform of free induction decay or spin echo measurements, thus removing the need for the application many $\pi$ pulses. We show that our method faithfully recovers the correct noise spectra for a variety of different environments (including $1/f$-type noise) and outperforms previous dynamical decoupling schemes while significantly reducing their experimental overhead. We also discuss the experimental feasibility of our proposal and demonstrate its robustness in the presence of statistical measurement error. Our method is applicable to a wide range of quantum platforms and provides a simpler path toward a more accurate spectral characterization of quantum devices, thus offering possibilities for tailored decoherence mitigation.