Contextuality Essential in Making Quantum Computers a Reality, Researchers Say

Quantum contextuality is important for making quantum computation possible, according to researchers at the University of Waterloo's Institute for Quantum Computing (IQC).

The team has confirmed, at least theoretically, that the concept of contextuality is important in designing a quantum computer system.

Unlike current computers that depend on binary system 0 and 1, quantum computers use Quantum bits or qubits. These qubits can exist in superposition, meaning that they can be a 0 or a 1 and everything in-between, simultaneously.

Researchers now say that physicists need to account for a weird ingredient in quantum computing - the contextuality - to make the quantum computers possible.

In everyday life, scientists can measure common properties such as color, size or shape. But, the same types of measurements can't be applied in quantum mechanics because sub-atomic particles behave differently than other particles, Tech Times reported. In quantum computing, the properties of the particles depend on the methods or the context used.  

A major problem in quantum computation is that there is no practical way of controlling the fragile quantum states. These systems need to be made in a noise-resistant environment. "Magic," in quantum computer terminology, refers to a particular approach in building the noise-resistant environment.

A practice called magic-state distillation can be used in reducing the noise or random data in a quantum computer. The scientists, in the current research, say that this "magic" only works with contextuality.

"Before these results, we didn't necessarily know what resources were needed for a physical device to achieve the advantage of quantum information. Now we know one," said Mark Howard, a postdoctoral fellow at IQC and the lead author of the paper, according to a news release. "As researchers work to build a universal quantum computer, understanding the minimum physical resources required is an important step to finding ways to harness the power of the quantum world."

The research is important because it shows other scientists what they need to be looking out for while designing quantum computers.

"These new results give us a deeper understanding of the nature of quantum computation. They also clarify the practical requirements for designing a realistic quantum computer," said Joseph Emerson, professor of Applied Mathematics and Canadian Institute for Advanced Research fellow. "I expect the results will help both theorists and experimentalists find more efficient methods to overcome the limitations imposed by unavoidable sources of noise and other errors."

The study was published in the journal Nature.