Unitary dynamics and resource trade-offs in a four-qubit isotropic Heisenberg XXX chain with tunable next-nearest-neighbor coupling

Fuente: arXiv
Saved in:
Bibliographic Details
Main Author: Khansari, Seyed Mohsen Moosavi
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866909025143095296
author Khansari, Seyed Mohsen Moosavi
author_facet Khansari, Seyed Mohsen Moosavi
contents This study derives the unitary dynamics of a four qubit Heisenberg XXX chain with tunable next nearest neighbor coupling $α$, starting from a Bell type initial state, and analyzes the evolution of quantum resources under the phase $ϕ= (α+ 1)t$. We provide closed form expressions for fidelity $F(ρ(0),ρ(t))$, coherence $C_{l_1}(ρ(t))$, and two qubit entanglement of formation $E_F(t)$ for subsystems $12$ and $34$, all of which are governed by $ϕ$. Fidelity exhibits periodic behavior with $F = \lvert \cos(ϕ/2) \rvert$ and a frozen regime at $α= -1$ where $F \equiv 1$. Coherence follows $C_{l_1}(ρ(t)) = \sin^2(ϕ/2)$, showing increasing sensitivity with $\lvert α+ 1 \rvert$ and vanishing at $α= -1$. Entanglement of formation $E_F(t)$ is an entropic function of $ϕ$, displaying banded oscillations and freezing at $α= -1$. The phase $ϕ$ unifies the behavior of all diagnostics, linking faster dynamics to larger $\lvert α+ 1 \rvert$ and revealing maximal sensitivity at $(α+ 1)t = π/4 + kπ/2$. This integrated framework provides exact benchmarks for small quantum devices and a clear pathway to noise, finite temperature, and larger system extensions.
format Preprint
id arxiv_https___arxiv_org_abs_2605_04429
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Unitary dynamics and resource trade-offs in a four-qubit isotropic Heisenberg XXX chain with tunable next-nearest-neighbor coupling
Khansari, Seyed Mohsen Moosavi
Quantum Physics
This study derives the unitary dynamics of a four qubit Heisenberg XXX chain with tunable next nearest neighbor coupling $α$, starting from a Bell type initial state, and analyzes the evolution of quantum resources under the phase $ϕ= (α+ 1)t$. We provide closed form expressions for fidelity $F(ρ(0),ρ(t))$, coherence $C_{l_1}(ρ(t))$, and two qubit entanglement of formation $E_F(t)$ for subsystems $12$ and $34$, all of which are governed by $ϕ$. Fidelity exhibits periodic behavior with $F = \lvert \cos(ϕ/2) \rvert$ and a frozen regime at $α= -1$ where $F \equiv 1$. Coherence follows $C_{l_1}(ρ(t)) = \sin^2(ϕ/2)$, showing increasing sensitivity with $\lvert α+ 1 \rvert$ and vanishing at $α= -1$. Entanglement of formation $E_F(t)$ is an entropic function of $ϕ$, displaying banded oscillations and freezing at $α= -1$. The phase $ϕ$ unifies the behavior of all diagnostics, linking faster dynamics to larger $\lvert α+ 1 \rvert$ and revealing maximal sensitivity at $(α+ 1)t = π/4 + kπ/2$. This integrated framework provides exact benchmarks for small quantum devices and a clear pathway to noise, finite temperature, and larger system extensions.
title Unitary dynamics and resource trade-offs in a four-qubit isotropic Heisenberg XXX chain with tunable next-nearest-neighbor coupling
topic Quantum Physics
url https://arxiv.org/abs/2605.04429