Physicists have extended the lifespan of magnons—tiny magnetic waves that can carry quantum information—from a few hundred nanoseconds to 18 microseconds, nearly a 100-fold improvement over previous records. This achievement could pave the way for highly compact quantum computers, potentially no larger than a 1-cent coin.
Led by Andrii Chumak at the University of Vienna, the international research team also discovered that magnons are not fundamentally constrained by the laws of physics. Instead, their longevity depends on the quality of the material through which they propagate. The study was published in Science Advances.
Magnons are tiny magnetization waves that move through magnetic materials like ripples spreading across water. Unlike photons, which can move through free space or optical fibers, magnons propagate only within magnetic solids.
Nanoscale Magnons for Compact Quantum Technologies
Their nanometer wavelengths enable compact circuits, while their interactions with other particles support hybrid quantum technologies and sensing.
One of the greatest obstacles to advancing magnon-based technology has long been the particles’ exceptionally short lifespan. Lasting only a few hundred nanoseconds, magnons decayed too quickly to serve as reliable carriers or storage media for quantum information.
The latest research marks a major step forward by extending magnon lifetimes to as long as 18 microseconds. This dramatic improvement transforms them from short-lived excitations into stable carriers of quantum information. Magnons’ extended lifetimes make them a promising alternative to superconducting qubits.
The breakthrough came from combining two key approaches.
A New Approach to Extending Magnon Lifetimes
First, the researchers moved beyond traditional uniform magnons and produced short-wavelength magnons instead. These smaller excitations resist crystal imperfections, reducing magnon decay.
The team cooled pure YIG spheres to 30 millikelvin, suppressing thermal disruptions and extending magnon coherence.
One of the most unexpected findings was the discovery of the true factor limiting magnon lifetimes.
By examining three YIG spheres with varying degrees of purity, the researchers identified a strong relationship between material quality and magnon stability. The cleaner and more defect-free the crystal, the longer the magnons remained intact. Remarkably, even the lowest-quality sample achieved a lifetime beyond those reported in all previous studies.
Material Purity Holds the Key to Longer Magnon Lifetimes
These findings indicate that extending magnon lifetimes is likely to depend more on improvements in materials engineering than on overcoming fundamental physical restrictions. As scientists develop purer magnetic materials, they could extend magnon coherence times even further.
With lifetimes extended to 18 microseconds, magnons are no longer just short-lived excitations but could become practical tools for quantum technologies. They may function as dependable quantum memory elements and efficient, low-loss channels for transferring quantum information across a chip.
Researchers propose magnons as a “quantum bus” to connect many qubits and enable communication between diverse quantum technologies.
The research is based on experiments conducted by Rostyslav Serha as part of his doctoral work. Led by the University of Vienna with partners in the U.S., Germany, and Ukraine, the project included coauthor Kaitlin McAllister through the Vienna Doctoral School in Physics, which supports outstanding international master’s students.
Read the original article on: sciencedaily
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