Los Alamos team measures quantum entanglement in solids for first time using neutron bombardment

Quantum Entanglement in Solids Measured for First Time Using Neutron Bombardment

A team at Los Alamos National Laboratory has achieved a breakthrough in measuring quantum entanglement within solid-state materials. Published in Physics on 8 April 2026, the study introduces a novel technique to quantify entanglement in solids through neutron bombardment. This method analyzes neutron interactions with materials to calculate Quantum Fisher Information (QFI), a metric that indicates the minimum number of entangled particles required to influence neutron behavior. The technique, presented at the American Physical Society Global Physics Summit, marks the first direct measurement of entanglement in solid-state systems. The Physics publication highlights its significance as a foundational contribution to quantum physics, with potential applications in both theoretical and practical research.

Validating the Method Through Experimental Testing

The method was tested on magnetic materials, including a potassium-copper-fluorine crystal, where experimental results closely matched theoretical simulations. Pontus Laurell of the University of Missouri noted the consistency between observed data and computational models, affirming the method’s validity. This approach operates independently of existing mathematical models or material perfection, making it adaptable for diverse applications. Future research will focus on measuring QFI near phase transitions—points where theoretical models often fail—potentially uncovering new quantum phenomena. For example, studying entanglement dynamics during phase transitions may reveal novel quantum phases or materials with enhanced properties, such as superconductors or topological insulators. The Los Alamos team’s ability to bypass traditional models underscores the method’s flexibility, enabling exploration of entanglement in systems where conventional approaches are insufficient.

“Pontus Laurell of the University of Missouri noted the consistency between observed data and computational models, affirming the method’s validity.”

Quantum Fisher Information as a Measurement Tool

Quantum Fisher Information (QFI) is a critical tool in quantum metrology, quantifying the sensitivity of a quantum state to parameter changes. It defines the precision limits of measurements through the Quantum Cramér-Rao Bound (QCRB). In the Los Alamos study, QFI was used to assess entanglement levels by analyzing neutron interactions. A parallel study in Nature Physics demonstrated its application in solid-state qubits, where researchers measured QFI in nitrogen-vacancy (NV) center qubits within diamonds using Ramsey interferometry to probe magnetic field sensitivity. By optimizing pulse sequences and mitigating decoherence, they achieved experimental variance matching QCR, validating the qubit’s potential for high-precision sensing. The NV center study combined quantum optics and solid-state physics, employing spin-echo techniques and low-temperature operation to suppress noise, ensuring stable coherence times. These methods are essential for achieving the QCRB, representing the theoretical limit of measurement precision in quantum systems.

Expanding Applications Beyond Traditional Quantum Systems

The dual applications of QFI—whether in neutron-based entanglement detection or qubit parameter estimation—highlight its versatility. In both cases, QFI serves as a bridge between theoretical models and experimental validation, enabling researchers to push quantum measurement boundaries. The Los Alamos method introduces a novel approach by leveraging solid-state interactions, expanding QFI’s utility beyond traditional quantum systems. For instance, the neutron bombardment technique bypasses the need for direct observation of entangled particles, a challenge in solids where interactions are inherently complex. This innovation opens new pathways for studying entanglement in environments where traditional methods are impractical, such as high-density materials or systems with strong electromagnetic coupling.

Technical Innovations in Neutron Bombardment

The neutron bombardment technique represents a significant technical innovation. By bombarding materials with neutrons and analyzing scattering patterns, the Los Alamos team bypassed the need for direct observation of entangled particles. This method circumvents the challenges of isolating individual particles in solids, where interactions are complex. The NV center study, meanwhile, employed Ramsey interferometry—a technique using microwave pulses to manipulate qubit states—to measure magnetic field sensitivity. Both approaches required overcoming decoherence, a major hurdle in quantum systems. The Los Alamos team addressed this by refining neutron detection protocols, while NV center researchers used spin-echo techniques and low-temperature operation to suppress noise. These strategies are critical for maintaining quantum state coherence, essential for accurate entanglement measurement.

Interdisciplinary Collaboration in Quantum Research

Collaboration across disciplines was essential. The neutron method drew on nuclear physics and materials science, while the NV center study combined quantum optics and solid-state physics. These interdisciplinary efforts underscore the growing convergence of fields in quantum research. The ability to measure entanglement in solids opens new avenues for studying quantum coherence in complex environments, with implications for fundamental science and applied technologies. For example, the NV center study’s success in validating QCRB suggests broader applications in quantum metrology, such as improving the precision of gravitational wave detectors or atomic clocks. Additionally, the discovery of hidden topological structures in entangled light, reported in Science Daily, highlights the diversity of quantum systems being explored. While this work focuses on photons, it complements solid-state studies by expanding the toolkit for understanding entanglement’s role in nature.

Implications for Quantum Technologies

The ability to measure entanglement in solids has profound implications for quantum technologies. In quantum computing, entangled states are crucial for error correction and parallel processing. Quantifying entanglement in solid-state systems allows researchers to design more efficient qubit architectures and optimize material properties for scalability. For quantum communication, entanglement enables secure information transfer via quantum key distribution. The Los Alamos method could enhance the reliability of entangled networks by providing a direct way to assess entanglement quality in physical materials. This is particularly important for long-distance quantum communication, where maintaining entanglement over large distances remains a challenge.

Applications in Quantum Sensing

Beyond computing and communication, the technique has applications in quantum sensing. The NV center study demonstrated that solid-state systems can achieve sub-quantum-limited precision in magnetic field measurements, a capability that could revolutionize fields like geophysics and medical imaging. For instance, in geophysics, such precision could enable the detection of underground structures or subsurface water reservoirs, improving resource exploration. In medical imaging, it could enhance the resolution of techniques like magnetic resonance imaging (MRI), allowing for earlier detection of diseases such as cancer. The discovery of hidden topological structures in entangled light, reported in Science Daily, further highlights the potential for new quantum technologies. While this work focuses on photons, it complements solid-state studies by expanding the toolkit for understanding entanglement’s role in nature.

Future Directions in Research

The next phase of research will focus on refining the neutron-based entanglement measurement technique to study entanglement dynamics during phase transitions. These transitions, where materials shift between ordered and disordered states, are critical for understanding quantum phase behavior. The Los Alamos team plans to measure QFI in systems undergoing such transitions, potentially revealing how entanglement evolves under extreme conditions. This could lead to the discovery of new quantum phases or materials with enhanced properties, such as high-temperature superconductors or topological materials with unique electronic properties. Meanwhile, the NV center study’s success in validating QCRB suggests broader applications in quantum metrology. Researchers are exploring how to integrate QFI measurements into existing quantum technologies, such as gravitational wave detectors or atomic clocks. Additionally, the discovery of hidden topological structures in entangled light, reported in Science Daily, highlights the diversity of quantum systems being explored. While this work focuses on photons, it complements solid-state studies by expanding the toolkit for understanding entanglement’s role in nature. Together, these advancements position quantum entanglement as a central pillar of next-generation technologies, with solid-state systems playing a pivotal role in their development.