Future Quantum Computers May Be Powered By Crystals

Physicists are exploiting the weird ways atoms interact with each other to build quantum computers. 

Atomic defects in some crystals may help unleash the potential of the quantum computing revolution, according to discoveries made by Northeastern University researchers. The scientists said they had discovered a new way to make a quantum bit using the crystals. Advances in quantum technologies, which deploy the properties of quantum physics called entanglement, could allow for more powerful and energy-efficient devices. 

"Entanglement is a fancy word for creating a relationship between particles that makes them act like they are bonded together," Vincent Berk, CRO & CSO of the quantum computing company Quantum Xchange told Lifewire in an email interview.

"This relationship is special in that it allows actions on one particle to have an effect on another. This is exactly where the power of computation comes in: when the state of one thing can change or affect the state of another. In fact, based on this crazy entanglement bond, we are able to represent all the possible outcomes of a computation in just a few particles."

Quantum Bits

Researchers explained in a recent paper in Nature that defects in a particular class of materials, specifically, two-dimensional transition metal dichalcogenides, contained the atomic properties to make a quantum bit, or qubit for short, which is the building block for quantum technologies.

"If we can learn how to create qubits in this two-dimensional matrix, that is a big, big deal," Arun Bansil, a physics professor at Northeastern and co-author of the paper, said in the news release. 

Bansil and his colleagues sifted through hundreds of different material combinations to find those capable of hosting a qubit using advanced computer algorithms. 

"When we looked at a lot of these materials, in the end, we found only a handful of viable defects—about a dozen or so," Bansil said. "Both the material and type of defect are important here because in principle there are many types of defects that can be created in any material."

A critical finding is that the so-called "antisite" defect in films of the two-dimensional transition metal dichalcogenides carries something called "spin" with it. Spin, also called angular momentum, describes a fundamental property of electrons defined in one of two potential states: up or down, Bansil said. 

One fundamental principle of quantum mechanics is that things like– atoms, electrons, photons – constantly interact to a greater or lesser extent, Mark Mattingley-Scott, Managing Director EMEA at the quantum computing company Quantum Brilliance, said in an email. 

"Quantum computers exploit this interdependency between qubits, which are essentially the simplest possible quantum mechanical system, to drastically increase the number of solutions we can explore in parallel when we run a quantum program," he added. 

Quantum Leap

Despite the recent breakthrough in qubits, don't expect quantum computers to replace your laptop anytime soon. Researchers still don't know the best physical system for building a quantum computer, Michael Raymer, a physics professor at the University of Oregon who studies quantum computing, told Lifewire in an email. 

"It's likely that in the next decade, there will be no large-scale universal QC that can solve any well-posed quantum problem," Raymer said. "So, people are building prototypes using various material 'platforms.'"

Some of the most advanced prototypes use trapped ions, including those built by companies like ionQ and Quantinuum. "These have the advantage that all atoms of a single type (say sodium) are strictly identical, a highly useful property," Raymer said. 

Future applications for quantum computing are limitless, boosters say. 

"Answering this question is akin to answering the same question about digital computers back in the 1960s," Raymer said. "No one correctly predicted the answer then, and no one can do so now. But the scientific community has every confidence that, if the technology succeeds, it will be equally impactful as the semiconductor revolution of the 1990s-2000s."