New Discovery Brings Coin-Sized Quantum Computers Closer to Reality

For years, scientists have viewed magnons as one of the most promising building blocks for next-generation quantum technologies. Yet one major obstacle has stood in the way: magnons decay almost immediately after they are created, making them unsuitable for practical quantum computing.

Now, researchers led by physicist Andrii Chumak at the University of Vienna have overcome this challenge by extending magnon lifetimes to an unprecedented 18 microseconds—nearly 100 times longer than previously achieved. Even more importantly, the team found that the remaining limitations are caused by imperfections in the material rather than fundamental laws of physics. The discovery opens a realistic path toward compact quantum processors that could one day be as small as a one-cent coin.

Figure 1. Coin-Sized Quantum Computers.

Why Magnons are so Important

Magnons are tiny waves of magnetization that travel through magnetic materials, much like ripples moving across the surface of a pond. Unlike photons, which travel through air or optical fibers, magnons remain confined within solid materials. Figure 1 shows coin-sized quantum computers.

Because their wavelengths can shrink to the nanometer scale, magnon-based circuits could be built on chips comparable in size to those inside modern smartphones. Magnons also interact naturally with other quantum particles, including phonons and photons, making them attractive for hybrid quantum devices, advanced sensing technologies, and future quantum communication systems.

Their biggest drawback has always been their extremely short lifespan. Previous experiments could keep magnons alive for only a few hundred nanoseconds—far too little time to store or transfer quantum information effectively.

Extending Magnon Lifetimes

To overcome this limitation, the research team combined two innovative strategies. First, they generated short-wavelength magnons, which are less vulnerable to defects on the surface of magnetic crystals than conventional magnons. Second, they cooled ultra-pure spheres of yttrium iron garnet (YIG) to just 30 millikelvin—only a tiny fraction of a degree above absolute zero—using a specialized cryostat. At these ultra-low temperatures, the thermal activity that normally destroys magnons is almost completely eliminated.

The experiments revealed that magnon lifetimes reached as long as 18 microseconds, a dramatic improvement over previous records. At these timescales, magnons become stable enough to serve as reliable carriers of quantum information, placing them alongside superconducting qubits used in many of today's leading quantum computing platforms.

Material Purity Holds the Key

Perhaps the study's most significant finding is that magnon lifetimes are no longer limited by the laws of physics. Instead, the primary barrier is the presence of tiny impurities within the crystal material.

The researchers tested three yttrium iron garnet samples with different purity levels and found a clear trend: the purer the crystal, the longer the magnons survived [1]. Even the least pure sample outperformed all previous records, suggesting that future improvements may come simply by manufacturing cleaner materials rather than discovering entirely new physical principles.

A Step Toward Scalable Quantum Computing

With lifetimes now extending into the microsecond range, magnons could evolve from short-lived quantum signals into dependable quantum memories and low-loss communication channels within quantum chips. They may eventually function as a "quantum bus," linking hundreds of qubits through a shared pathway and solving one of the biggest engineering challenges in building scalable quantum computers.

Because magnons can also interact with multiple quantum systems, they have the potential to act as universal connectors within hybrid quantum architectures, allowing different quantum technologies to communicate seamlessly. If researchers continue improving material quality, magnons could become a cornerstone of future quantum computers—bringing powerful, energy-efficient devices no larger than a coin significantly closer to reality.

References:

1. https://scitechdaily.com/new-discovery-could-unlock-quantum-computers-the-size-of-a-coin/

Cite this article:

Keerthana S (2026), Breakthrough May Enable Coin-Sized Quantum Computers, AnaTechMaz, pp.517