Researchers from the University of Warsaw and the University of British Columbia have identified how a fundamental quantum excitation known as a lone spinon, a single, unpaired spin, can emerge in magnetic models.
The breakthrough, recently published in Physical Review Letters https://doi.org/10.1103/stvg-lg9h, could impact the development of future technologies, including quantum computers and new magnetic materials.
“This discovery represents a significant contribution to our understanding of the nature of magnetism and could have implications for the development of future technologies such as quantum computers and new magnetic materials,” representatives of the Faculty of Physics at the University of Warsaw stated in a press release.
Magnets, which are crucial in technologies ranging from computer memory to electric motors and medical diagnostics, owe their properties to the quantum behavior of electrons—specifically, their spin. Spin is a fundamental characteristic of elementary particles, akin to electric charge or mass.
The theoretical groundwork for this research dates back to 1931, when physicist Hans Bethe devised a solution to the one-dimensional Heisenberg model, a fundamental framework for understanding quantum magnetism.
In 1981, physicists Ludwig Faddeev and Leon Takhtajan expanded on this by predicting that magnetic excitations could behave as if an electron “split” into two independent entities, known as spinons. These spinons, each carrying a spin value of 1/2, were believed to always occur in pairs.
The new study challenges that assumption.
A team led by physicists at the University of Warsaw and UBC showed that a single spinon can emerge in a one-dimensional Heisenberg system by adding just one spin to its ground state. This lone spinon behaves as a solitary quantum excitation.
Researchers also demonstrated the same effect using a simplified theoretical model known as the valence-bond solid (VBS) model. In this setup, most spins pair up in an ordered configuration, and a spinon is interpreted as an unpaired spin that can “travel” through the network.
“It is an important step towards a better understanding of the quantum properties of magnets,” the University of Warsaw team emphasized.
The lone spinon is not just a theoretical novelty—it reflects the deeper nature of strongly interacting electrons and quantum entanglement. Such quantum effects are central to high-temperature superconductivity, the fractional quantum Hall effect, and the principles behind quantum computing.
“Our research not only deepens our knowledge of magnets but may also have far-reaching implications in other fields of physics and technology,” concluded Professor Krzysztof Wohlfeld from the Faculty of Physics, University of Warsaw.
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