Unitary dynamics and resource trade-offs in a four-qubit isotropic Heisenberg XXX chain with tunable next-nearest-neighbor coupling
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Quantum Physics arXiv:2605.04429 (quant-ph) [Submitted on 6 May 2026] Title:Unitary dynamics and resource trade-offs in a four-qubit isotropic Heisenberg XXX chain with tunable next-nearest-neighbor coupling Authors:Seyed Mohsen Moosavi Khansari View a PDF of the paper titled Unitary dynamics and resource trade-offs in a four-qubit isotropic Heisenberg XXX chain with tunable next-nearest-neighbor coupling, by Seyed Mohsen Moosavi Khansari View PDF Abstract:We derive the unitary dynamics of a four-qubit isotropic Heisenberg XXX chain with tunable next-nearest-neighbor coupling $\alpha$, initialized in a Bell-type product state. Closed-form expressions are obtained for the state fidelity $F(\rho(0),\rho(t))$, the $l_1$-norm coherence $C_{l_1}(\rho(t))$, and the entanglement of formation $E_F^{12}(t)$ and $E_F^{34}(t)$ for the two-qubit subsystems (12) and (34). All quantities depend exclusively on the composite phase $\phi = (\alpha+1)t$. Fidelity obeys $F = |\cos(\phi/2)|$ and remains frozen at $F \equiv 1$ for $\alpha = -1$. Coherence follows $C_{l_1} = \sin^2(\phi/2)$, vanishing identically at $\alpha = -1$ and exhibiting sensitivity proportional to $|\alpha+1|$. The entanglement of formation is an entropic function of $\phi$, displaying banded oscillations and freezing at $\alpha = -1$. The phase $\phi$ unifies all observables, linking the rate of resource variation to $|\alpha+1|$ and identifying maximal sensitivity along $(\alpha+1)t = \pi/4 + k\pi/2$. This framework provides exact benchmarks for few-qubit quantum devices and a controlled pathway for extensions to noise, finite temperature, and larger systems. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2605.04429 [quant-ph] (or arXiv:2605.04429v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2605.04429 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Seyed Mohsen Moosavi Khansari [view email] [v1] Wed, 6 May 2026 02:47:21 UTC (676 KB) Full-text links: Access Paper: View a PDF of the paper titled Unitary dynamics and resource trade-offs in a four-qubit isotropic Heisenberg XXX chain with tunable next-nearest-neighbor coupling, by Seyed Mohsen Moosavi KhansariView PDF view license Current browse context: quant-ph new | recent | 2026-05 References & Citations INSPIRE HEP NASA ADSGoogle Scholar Semantic Scholar export BibTeX citation Loading... BibTeX formatted citation × loading... Data provided by: 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 Code, Data and Media Associated with this Article alphaXiv Toggle alphaXiv (What is alphaXiv?) Links to Code Toggle CatalyzeX Code Finder for Papers (What is CatalyzeX?) DagsHub Toggle DagsHub (What is DagsHub?) GotitPub Toggle Gotit.pub (What is GotitPub?) Huggingface Toggle Hugging Face (What is Huggingface?) ScienceCast Toggle ScienceCast (What is ScienceCast?) Demos Demos Replicate Toggle Replicate (What is Replicate?) Spaces Toggle Hugging Face Spaces (What is Spaces?) Spaces Toggle TXYZ.AI (What is TXYZ.AI?) Related Papers Recommenders and Search Tools Link to Influence Flower Influence Flower (What are Influence Flowers?) Core recommender toggle CORE Recommender (What is CORE?) Author Venue Institution Topic About arXivLabs arXivLabs: experimental projects with community collaborators arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website. Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them. Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs. Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)