A quantum state has been observed in a material where physicists previously believed it was completely impossible. This discovery is forcing scientists to rethink the fundamental rules that govern how electrons behave in certain materials.
An international team of researchers made this breakthrough. It could help advance quantum computing, improve the efficiency of electronic devices, and lead to the development of more advanced sensors and imaging technologies.
The quantum state in question is called a topological semimetal phase. Theoretically, it was predicted that this state might appear in the material CeRu₄Sn₆ (a compound of cerium, ruthenium, and tin) at extremely low temperatures. Experiments have now confirmed that this prediction is correct.
What does this mean?
At extremely low temperatures, close to absolute zero, CeRu₄Sn₆ reaches a quantum critical point. In this state, the material exists between two different phases, and quantum fluctuations become so strong that the material stops behaving like individual particles and instead behaves more like a collective wave pool.
Normally, quantum states are thought to arise from interactions between particles. For example, electrons acting as independent charge carriers. However, in this case, these behaviors emerge from quantum criticality itself.
Topology refers to a special kind of geometric structure inside a material. Topological states protect certain particle properties, even when neighboring particles attempt to disrupt them. It was previously believed that topological properties could not exist in a quantum critical state. But this research shows that both can coexist, and very strongly.
Researchers cooled CeRu₄Sn₆ close to absolute zero and applied an electric current. They observed the Hall effect, surprisingly without any magnetic field. Normally, a magnetic field is required to observe the Hall effect. Here, the bending of the electric current occurred due to the material’s internal topological properties, providing strong evidence of this unique quantum state.
Physicists stated:
“This was the key clue that allowed us to confirm that conventional theories must be revised.”
Where electron patterns were most unstable, meaning in the quantum critical region, the topological effects were strongest. In fact, quantum fluctuations themselves were stabilizing this new phase.
Strong electron interactions do not destroy topological states. Instead, they can create them. This represents a new type of quantum state with major practical potential. Researchers are now exploring whether similar states can be found in other materials.
This discovery fills an important gap in quantum physics. Scientists say they now know what to look for. It is not just a theoretical breakthrough, but a step toward transforming the deepest principles of quantum physics into real-world technology.
