Electron-nuclear Entanglement Advances Quantum Memories Using One-Tangles
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Controlling entanglement between electron and nuclear spins represents a significant challenge and opportunity for realising advanced quantum technologies, including quantum networks and highly sensitive sensors. Isabela Gnasso from Virginia Tech, Khadija Sarguroh from the University of Oxford, Dorian Gangloff from the University of Cambridge, and colleagues now demonstrate a powerful method for quantifying these interactions in a broad range of materials, extending previous work on diamond and silicon carbide to include systems with more complex nuclear spins, such as those found in quantum dots and rare-earth ions.
The team’s research introduces a technique, based on a metric called ‘one-tangling power’, to pinpoint conditions for maximising entanglement between an electron and surrounding nuclei, and crucially, to predict and optimise the coherence times of electron spins. This advancement offers a pathway towards creating robust quantum memories and enhancing the performance of solid-state quantum devices, particularly within (In)GaAs quantum dots where the team identifies specific parameter regimes for achieving sustained coherence. Central-spin systems, characterised by a single unpaired electron interacting with multiple nuclear spins, provide a platform for exploring fundamental aspects of quantum entanglement and its evolution over time. This approach allows detailed analysis of how entanglement changes over time, influenced by factors such as magnetic fields and interactions between spins, offering insights into the potential for utilising these systems in quantum technologies.
Nuclear Spin Coherence in Enriched Silicon-29 Solid-state systems, including quantum dots, rare-earth ions, and colour centres in diamond and silicon carbide, represent promising candidates for quantum networks, computing, and sensing applications. Researchers demonstrated that a key metric for assessing the suitability of nuclear spins as quantum memories is the degree to which they preserve quantum information over time.
The team employed pulsed electron spin resonance experiments to characterise the dynamics of nuclear spin coherence in isotopically enriched silicon-29, applying precisely timed microwave pulses to manipulate the nuclear spins and measuring the resulting signal to determine the coherence time.
Nuclear Spin Interactions and Qubit Dephasing A substantial body of research focuses on quantum information, specifically spin qubits and their interactions with nuclear spins. This interaction causes dephasing, or loss of quantum information, and is a major obstacle to building stable qubits. Researchers employ dynamical decoupling and control techniques to suppress dephasing, and are exploring using nuclear spins as a form of quantum memory, leveraging their long coherence times. Central spin systems, utilising a single electron spin coupled to a bath of nuclear spins, allow for studying many-body quantum phenomena and potentially creating novel quantum devices. Scientists are developing methods to entangle nuclear spins and use them to perform quantum gates, and are investigating quantum sensing, utilising spin qubits to detect weak magnetic fields. Materials science plays a crucial role, with researchers exploring different materials for hosting spin qubits and optimising their properties. Research is categorised into areas including characterising nuclear spin environments, optimising dynamical decoupling sequences, and exploring quantum repeaters and collective quantum memory. Entanglement Growth and Dephasing Time Prediction Researchers have established an analytical framework for understanding and optimising entanglement between electron spins and nuclear spins in solid-state systems. They developed a generalised concept called ‘one-tangling power’ to quantify the growth of entanglement and predict electron spin dephasing times, a key limitation in quantum technologies. By applying this metric to a model (In)GaAs quantum dot, the team pinpointed specific parameter regimes that maximise entanglement, even when employing dynamical decoupling techniques. The findings demonstrate that the analytical one-tangling power accurately matches numerical calculations, offering a computationally efficient method for predicting dephasing times and designing strategies to enhance coherence. Researchers verified this approach by simulating electron spin dynamics subject to dynamical decoupling, demonstrating the ability to model entanglement growth and identify conditions for minimising decoherence. Future work could explore the application of this framework to diverse material systems and investigate the potential for harnessing nuclear spins as long-lived quantum memories within quantum networks and sensors. 👉 More information🗞 Quantifying electron-nuclear spin entanglement dynamics in central-spin systems using one-tangles🧠 ArXiv: https://arxiv.org/abs/2512.14004 Tags: Rohail T. As a quantum scientist exploring the frontiers of physics and technology. My work focuses on uncovering how quantum mechanics, computing, and emerging technologies are transforming our understanding of reality. I share research-driven insights that make complex ideas in quantum science clear, engaging, and relevant to the modern world. Latest Posts by Rohail T.: Leo and MEO Satellite Links Enabled by Turbulence-Resistant Quantum Communication Systems December 18, 2025 Ground State Calculations Achieve 3 Orders of Magnitude Speedup with Tensor Networks December 18, 2025 Chemical Engineering Enables Altermagnetism in Two-Dimensional Metal-Organic Frameworks December 18, 2025