Theory of Two-Qubit $T_2$ Spectroscopy of Quantum Many-Body Systems

Quantum Physics [Submitted on 18 Mar 2026] Theory of Two-Qubit T_2 Spectroscopy of Quantum Many-Body Systems Hossein Hosseinabadi, Pavel E. Dolgirev, Sarang Gopalakrishnan, Amir Yacoby, Eugene Demler, Jamir Marino 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. Comments: 21 pages, 7 figures Subjects: Quantum Physics (quant-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Cite as: arXiv:2603.18176 [quant-ph]   (or arXiv:2603.18176v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2603.18176 Focus to learn more Submission history From: Hossein Hosseinabadi [view email] [v1] Wed, 18 Mar 2026 18:20:41 UTC (1,122 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-03 Change to browse by: cond-mat cond-mat.mes-hall References & Citations INSPIRE HEP NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)