Year: 2026
Type: article
Abstract: Multi-qubit quantum sensors are rapidly emerging as platforms that extend the capabilities of conventional single-qubit sensing. In this work we show how suitable pulse sequences applied to a two-qubit sensor enable separate extraction of the response and noise of a probed environment within a $T_2$ spectroscopy framework. By resorting to representative examples, we demonstrate that this approach can resolve the spatio-temporal spreading of correlations in a many-body system. In particular, the resulting correlated dephasing signal captures features such as the dispersion of low-energy excitations, which manifest as light-cone-like profiles in the propagation of correlations. We further show that non-equilibrium conditions, for instance those induced by external driving, can modify this profile by producing additional fringes outside the light-cone. As a complementary application, we demonstrate that the method clearly distinguishes between different transport regimes in the system, including ballistic spreading, diffusive broadening, and the crossover between them.
DOI: 10.1103/nql5-tb4m
Language: English
Topic: Quantum many-body systems
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: QuSeC-TAQS: Nanoscale Covariance Magnetometry with Diamond Quantum Sensors, G1650921002, NCCR SPIN: Spin Qubits in Silicon, G3180218165, G4855190166, Non-perturbative approaches to strongly correlated many-body systems, TRR 288: Elastisches Tuning und elastische Reaktion elektronischer Quantenphasen der Materie (ELASTOQMAT), G8510387532, G993971353
OpenAlex ID: W7139960643