Quantum Entanglement Control in Two-Spin-1/2 NMR Systems Through Magnetic Fields and Temperature

• URL: http://arxiv.org/abs/2512.01060v1
• Date: Sun, 30 Nov 2025 20:04:42 GMT
• Title: Quantum Entanglement Control in Two-Spin-1/2 NMR Systems Through Magnetic Fields and Temperature
• Authors: Fatemeh Khashami, Stefan Glöggler,
• Abstract summary: We show how entanglement depends on temperature and magnetic field strength, resulting in a threshold temperature beyond which entanglement vanishes.<n>At zero temperature, the system exhibits a quantum critical point, characterized by non-analytic behavior in the measure of entanglement.<n>These findings provide insights into the thermal control of quantum features, with implications for quantum-enhanced NMR, low-temperature spectroscopy, and emerging quantum technologies.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We investigate quantum entanglement in two-spin-1/2 NMR systems at thermal equilibrium under external magnetic fields. We derive closed-form analytical expressions for the entanglement of the system and show how the entanglement depends on temperature and magnetic field strength, resulting in a threshold temperature beyond which entanglement vanishes. We demonstrate that at zero temperature, the system exhibits a quantum critical point, characterized by non-analytic behavior in the measure of entanglement. We further develop analytical criterion for level crossing, which serves as a condition for identifying quantum critical points in both homonuclear and heteronuclear systems, and apply it to multiple settings to analyze their quantum critical points. We establish a direct link between the quantum entanglement quantifier and experimentally accessible NMR observables, enabling entanglement to be quantified through NMR signal processing. This provides a practical framework for characterizing quantum correlations using standard NMR experiments. These findings provide insights into the thermal control of quantum features, with implications for quantum-enhanced NMR, low-temperature spectroscopy, and emerging quantum technologies.

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