Scientists have always wondered whether ordinary materials are also secretly held together by quantum connections. Until now, there seems to be no way to answer this question. 

However, recently, a team of researchers has demonstrated a technique that can directly detect entanglement inside solids. So instead of guessing or relying purely on theory, scientists can now directly measure how entangled a material is—an essential step for designing better quantum devices.

Moreover, according to the researchers, their technique works even when there is no perfect theoretical model of the material, and the sample is not pure (which is often the case in real-world materials).

“We’ve found that it works 100 percent,” Allen Scheie, one of the researchers and a condensed matter physicist at Los Alamos National Laboratory in New Mexico, said.

Turning neutron echoes into a map of entanglement

The problem scientists faced wasn’t a lack of theory but a lack of tools. Traditional methods like Bell tests can confirm entanglement between a few particles, but they break down when dealing with the trillions of interacting particles inside a solid. 

Materials are messy, complex, and often imperfect, making it extremely difficult to tell whether entanglement is present, let alone measure how much of it exists.

The researchers tackled this by refining neutron scattering, a technique that has been around since the 1950s. In simple terms, they fired neutrons at a material and observed how those neutrons bounced off. 

These scattered neutrons carry subtle fingerprints of what’s happening inside a material—how atoms are arranged and how their quantum properties behave. However, the real breakthrough came from combining this old tool with a newer concept called quantum Fisher information (QFI). 

QFI is a mathematical quantity that can act like an entanglement meter. Instead of trying to track every particle individually, it tells scientists the minimum number of particles that must be entangled to produce the observed signal.

By carefully analyzing the neutron data, the team could calculate the QFI for a material—and from that, infer how deeply entangled its internal particles are.

Next, to test whether this approach really works, the researchers studied well-understood magnetic materials, including a crystal made of potassium, copper, and fluorine. As this material has already been simulated in detail, they could compare their experimental results with theoretical predictions. 

The comparison led to “a remarkably close match between the experimental and theoretical curves,” Pontus Laurell, one of the researchers and an assistant professor at the University of Missouri, said.

A highly flexible quantum approach

Earlier studies had proposed QFI as a possible entanglement witness because of its potential to become an effective tool to measure how sensitive a quantum system is to tiny changes.

However, they lacked a clear, practical way to measure it experimentally. This work appears to bridge that gap, turning a theoretical idea into a usable laboratory tool.

If this method holds up across more systems, it could transform how scientists explore quantum materials. Materials with high entanglement could become the backbone of future quantum computers or ultra-secure communication networks.

An exciting next step would be to study what happens near a quantum phase transition—a point where a material suddenly changes its state, similar to water freezing into ice, but driven by quantum effects. 

At these critical points, theory predicts that entanglement may spike dramatically, but models often fail to describe what actually happens. The researchers plan to measure QFI in this regime, where a genuine discovery could emerge.

The study was recently presented at the American Physical Society Global Physics Summit.