Southwest Quantum Information and Technology

Spectroscopy of quantum and non-Gaussian noise

Presenting Author: Leigh Norris, Dartmouth
Contributing Author(s): Gerardo Paz-Silva and Lorenza Viola

Precisely characterizing the decoherence effects arising from coupling to a noisy environment is essential for designing optimized error correction strategies and validation protocols for realistic quantum information processors. This challenge has prompted much of the recent interest in quantum noise spectroscopy, which seeks to estimate the spectral properties of noise affecting a target quantum system. Despite considerable theoretical and experimental advances, this effort has largely been confined to the case of classical, Gaussian phase noise on a single qubit. We overcome these limitations by introducing quantum noise spectroscopy protocols for both quantum and non-Gaussian phase noise. For realistic systems that include a pair of excitons coupled to a phonon bath and a qubit undergoing quadratic dephasing at an optimal point, we numerically demonstrate reconstruction of the asymmetric spectra unique to quantum environments and the polyspectra associated with higher order cumulants of non-Gaussian noise. In both cases, spectral reconstructions enable us to accurately predict the dynamics of qubits coupled to these noise sources. In addition to the practical value in characterizing a larger class of noise processes, this work highlights dynamical and spectral signatures unique to quantum and non-Gaussian noise sources.

Read this article online: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.150503, https://arxiv.org/pdf/1609.01792v2.pdf

(Session 10 : Saturday from 9:15am - 9:45am)