Quantum physics is often associated with particles so tiny that they are impossible to see with the naked eye. For decades, scientists have observed strange quantum behaviors in individual atoms, molecules, and photons carefully isolated from the outside world. But a new experiment suggests that some of those same effects can also emerge in objects large enough to fit in the palm of a hand.Researchers at TU Wien in Austria have detected a high degree of quantum entanglement inside a centimeter-sized crystal known as a strange metal. Their findings, published in Nature Physics on June 15, offer a rare glimpse of quantum behavior in a macroscopic material and could help scientists better understand materials that may play a role in future technologies. First, let's understand what quantum entanglement is.What is quantum entanglement?Quantum entanglement is one of the strangest and most important ideas in modern physics. It describes a situation in which two or more particles become linked in such a way that the state of one particle is directly connected to the state of another, even when they are separated by large distances.As explained by the California Institute of Technology (Caltech), entanglement occurs when particles such as photons or electrons become connected and behave as parts of a larger quantum system rather than as independent objects. Scientists describe this as an "emergent property," meaning the phenomenon arises from the relationship between particles rather than from any individual particle itself.From Schrödinger's cat to an anthillOne of the most famous thought experiments in physics is Erwin Schrödinger's cat, which imagines a cat being both dead and alive at the same time because of quantum uncertainty. Scientists have long debated whether such quantum effects can exist in larger objects."Our approach is different," says Prof. Silke Bühler-Paschen from the Institute of Solid State Physics at TU Wien. "We do not try to bring the crystal as a whole into a superposition of two states. Instead, we ask whether its constituents are—collectively—in such a state of entanglement."The experiment, she explained, is less like Schrödinger's cat and more like an anthill responding as one unit. "When it is disturbed, it is not a single ant that reacts, but the entire colony as a collective."A crystal that responds as a groupTo investigate the material, researchers created a crystal made of cerium, palladium, and silicon. The crystal belongs to a class of materials known as strange metals, which have puzzled scientists for years because they do not behave like ordinary metals.At a research facility in Grenoble, France, the team fired neutrons at the crystal and studied how it reacted. "The quantum Fisher information quantifies how sensitively a quantum system responds to a change," explains Bühler-Paschen. "For a collection of independent particles, the response is limited because each particle contributes on its own. However, if the particles are entangled, the entire system can respond more strongly than the sum of its individual parts."The researchers used a concept called quantum Fisher information to measure that response and estimate the degree of entanglement inside the material.One neutron, many particlesThe results surprised the team. "In a normal material, one would expect a neutron to transfer its energy to an individual particle," says Federico Mazza. "But by analyzing the data using the quantum Fisher information, we found a response that cannot be explained in terms of independent particles. Instead, it indicates that groups of at least nine quantum-entangled entities act collectively."The finding provides direct evidence that large groups of particles inside the crystal are behaving in a coordinated quantum state.Why it mattersScientists have been trying to understand strange metals because similar behavior appears in high-temperature superconductors, materials that can conduct electricity with little or no resistance under certain conditions.The new study may also help explain an unusual discovery reported by researchers in 2025, when electric current flowing through strange metals was found to be remarkably quiet, producing less noise than expected."What we see here is not a detail of one particular material, but a general physical principle," says Fakher Assaad from the University of Würzburg, lead theorist of the work. "Strong entanglement appears to be directly linked to the unusual behavior of strange metals."Researchers believe the work could eventually influence future quantum technologies, including ultra-sensitive measurement tools."The results are a great success for us," says Bühler-Paschen. "They confirm that our unusual approach of using methods from quantum information science for solid-state physics studies of novel materials can reveal fundamentally new insight."The team now hopes to explore whether strange metals could one day be used in practical quantum applications."We want the transfer of knowledge between the two fields to also work in the other direction. Our aim is to explore whether strange metals may one day find applications in quantum technologies—for example, in high-precision measurements for quantum metrology."