The digital revolution that we all imagine – instantaneous calculations, highly advanced medical simulations, increasingly precise climate models – passes through a technology that is as promising as it is delicate: the quantum computer. A machine capable, at least on paper, of solving problems that today would require astronomical times. Yet, there is one detail that holds everything back: the extreme fragility of quantum systems.
All it takes is a minimal temperature variation, an imperceptible vibration, a microscopic magnetic disturbance and the quantum states become misaligned, generating errors that propagate in a few moments. It’s like building a house of cards in the middle of an invisible draft.
In this unstable scenario, a group of researchers has observed something that could change the rules of the game. The protagonist of the discovery is an alloy composed of niobium and rheniumtwo rare transition metals, which in laboratory tests showed unexpected and, in some ways, revolutionary behavior.
An experiment that overturns “classical” physics
To understand why this alloy – known as NbRe – is attracting so much attention, you have to take a step inside the laboratory. The researchers built a three-layer structure: in the center a very thin film of NbRe, on the sides two magnetic layers capable of orienting in the same direction or in opposite directions. In a traditional superconductor, changing the orientation of the magnets produces a change in electrical resistance that is predictable and consistent with established theory. Here, however, the opposite happened.
The electrical signal showed an inversion compared to what would be expected from a “classical” superconductor. It was the professor who documented the anomaly Jacob Linder of the Norwegian University of Science and Technology, who interpreted the result as a possible indication of a rare phenomenon: electronic coupling with spin aligned.
Simply put, electrons within the material appear to move in pairs while maintaining the same magnetic direction, rather than canceling it as happens in conventional superconductors. And this is where a fascinating scenario opens up.
Why spin can change the future of quantum computing
In traditional superconductors, electrons pair in a way that cancels out each other’s tiny magnetic property, called spin. The result is a current flow with no resistance, but also no magnetic information.
Some very rare materials, defined triplet superconductorsinstead seem to allow the electron pairs to maintain the same magnetic orientation. This means being able to transport at the same time electric current and magnetic information without dissipating energy.
For quantum technology, which lives and dies on the stability of quantum states, such behavior represents almost a “Holy Grail”. Reducing energy dissipation means reducing thermal noise, and reducing noise means increasing the precision of qubits, the fundamental units of quantum computing.
However, Professor Linder urges caution: it is too early to officially declare that NbRe is a triplet superconductor. Independent replications of the experiment and in-depth checks are needed to exclude hidden magnetic effects or experimental artifacts.
An atomic structure that makes the difference
A key element of this alloy concerns its internal structure. NbRe is a material, meaning its atoms are not arranged according to perfect mirror symmetry. This small asymmetry changes the way electrons pair and allows a combination of two pairing modes that normally remain separate. The consequence is an electronic flexibility that could explain the anomalous current behavior observed in the tests.
A particularly interesting detail concerns the origin of the effect: the researchers believe that it arises from the intrinsic structure of the material, and not from extremely precisely designed interfaces or sophisticated surface treatments. If this hypothesis were confirmed, industrial integration would become much more realistic.
Extreme cold, but less prohibitive
Like any superconductor, NbRe also works at very low temperatures. It becomes superconductive around 7 Kelvin, i.e. around -266 degrees Celsius. It’s a cryogenic temperature, sure, but significantly more “manageable” than other materials that require temperatures close to 1 Kelvin.
Reducing the intensity of the necessary cooling means containing part of the energy costs of quantum infrastructures, which today represent one of the main obstacles to large-scale deployment.
However, the challenge remainsquantum error. In quantum systems, small errors multiply rapidly. Complex real-time correction systems are used today, but any improvement in the stability of the base material can make the difference between a fragile prototype and a truly operational machine.
From basic research to spintronics
The NbRe alloy can be manufactured in the form of very thin films, compatible with the deposition processes used in the semiconductor industry. This aspect opens up concrete perspectives: less complexity in interfaces also means less possibility of hidden errors. The interest, however, is not limited to quantum computing. There is another area that carefully observes these results: the spintronicsthat is, electronics that use the spin of electrons to transmit information, in addition to their charge.
If spin could travel through a superconductor without resistance, magnetic memories and superconducting circuits could communicate directly with a drastic reduction in energy losses. In a world that seeks increasingly efficient and sustainable solutions from an energy point of view, this detail is by no means secondary. The study was published on Physical Review Lettersone of the most authoritative journals in the field of physics.
The future of NbRe will now depend on the replicability of experiments and the ability to integrate the material into real devices. It could become a concrete platform for low-loss quantum control or remain an elegant promise confined to laboratories. In the meantime, physics has rekindled hope. And when it comes to quantum technology, every glimmer counts.
