Entanglement Seen in Solids
Researchers have reportedly measured quantum entanglement inside a solid for the first time using neutrons — that matters because it moves entanglement studies out of isolated particles and into materials you can engineer. The result, shared widely on X this week, suggests neutron‑based techniques could become a new practical tool to probe and eventually exploit entangled states in solid‑state quantum devices ( ).
Quantum entanglement is the rule that lets two quantum objects share one linked state, so measuring one is partly like reading the other half of the same coin toss. Physicists have shown that link cleanly in photons, atoms, and trapped ions for years, but a whole crystal is harder because billions of particles are jostling at once. (newscientist.com) A solid is the messy version of quantum physics. Instead of two carefully isolated particles on an optics table, you have a bulk material where spins, vibrations, and heat all pile together and hide the signal you want. (aps.org) The trick in this story is neutrons. A neutron has no electric charge, so it can pass deep into a crystal and scatter off the tiny magnetic moments of electrons without getting scrambled as badly as charged probes do. (ornl.gov) Scientists have used neutron scattering since the 1950s to map where atoms sit and how magnetic waves move through materials. What they could not do reliably was turn those scattering patterns into a direct yardstick for how much entanglement was hiding inside the solid. (newscientist.com) That yardstick is called quantum Fisher information. In plain English, it is a number that tells you how many particles must be acting as a linked quantum group to produce the signal you measured. (newscientist.com) Allen Scheie of Los Alamos National Laboratory and colleagues spent more than five years building a neutron-based procedure to extract that number from real materials. New Scientist reported on April 8, 2026 that the team says the method now works across different solids rather than only in idealized theory. (newscientist.com) One of the test cases was potassium copper fluoride, a crystal written chemically as KCuF3 that physicists have used for decades as a model one-dimensional quantum magnet. Because that material is so well studied, the team could compare the neutron result against detailed computer simulations of the crystal’s internal quantum behavior. (aps.org, newscientist.com) This did not come out of nowhere. A 2021 Physical Review B paper by Scheie, Pontus Laurell, and coauthors showed that neutron data from KCuF3 could already reveal entanglement, and Oak Ridge National Laboratory said that work laid the foundation for a general detection protocol in quantum spin systems. (aps.org, ornl.gov) What looks new in 2026 is the claim that the approach has crossed from “promising witness” to a clear measurement procedure researchers can apply to different materials. Scheie told New Scientist the group has established that it works “100 per cent” and is now standardizing the steps needed for other solids. (newscientist.com) That opens a more practical path for quantum materials. If a neutron beam can tell engineers which crystal actually contains the large linked states needed for quantum computing or quantum communication, it becomes a screening tool for devices instead of just a physics demo. (newscientist.com, ornl.gov) There is a second thread here too. In February 2025, researchers at the Technical University of Munich reported creating entangled neutron beams on a standard neutron scattering instrument, which means the same family of machines is getting better both at making entangled probes and at reading entangled matter. (frm2.tum.de) The result does not mean your laptop is getting a quantum crystal next year. It means entanglement is starting to move out of fragile one-off setups and into bulk materials that labs can grow, cool, hit with neutrons, and compare side by side. (newscientist.com, aps.org)
