Instability-Enhanced Quantum Sensing with Tunable Multibody Interactions

Quantum Physics [Submitted on 6 Apr 2026] Instability-Enhanced Quantum Sensing with Tunable Multibody Interactions Bidhi Vijaywargia, Jorge Chávez-Carlos, Francisco Pérez-Bernal, Lea F. Santos Dynamical instabilities can amplify small perturbations into measurable signals, offering a route to quantum-enhanced sensing. This mechanism was experimentally demonstrated in a collective-spin system with quadratic interactions, described by a twisting-and-turning Hamiltonian, where quantum evolution near an unstable point leads to exponential growth of spin fluctuations, enabling metrological gain beyond the standard quantum limit. Here, we show that a quartic extension of this Hamiltonian substantially increases the amplification. The additional nonlinear term reshapes the phase-space structure, generating new unstable points and accelerating signal amplification. As a result, enhanced sensitivity is achieved within experimentally accessible coherence times. Remarkably, even at fixed instability rate (equal Lyapunov exponent), multibody interactions outperform the quadratic case due to enhanced short-time dynamics. We analyze the classical and quantum behavior of the multibody model and discuss its experimental implementations. Our results identify phase-space curvature as a resource for optimizing the speed and performance of quantum sensors. Comments: 15 pages, 6 figures Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.05047 [quant-ph]   (or arXiv:2604.05047v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.05047 Focus to learn more Submission history From: Bidhi Vijaywargia [view email] [v1] Mon, 6 Apr 2026 18:01:02 UTC (3,485 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-04 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?)