Researchers crack quantum computing conundrum

Quantum computers may be easier to build than first thought, according to a new paper from scientists at Imperial College London and the University of Queensland.

The technology has shown enormous potential, but building a system of any real size is difficult because they are fragile and prone to errors in data streams.

The new paper uses a new theory of quantum data analysis that improves data reading, allowing quantum computers to tolerate data error rates of almost 25 per cent.

"Just as you can often tell what a word says when there are a few missing letters, or you can get the gist of a conversation on a badly connected phone line, we used this idea in our design for a quantum computer," said Sean Barrett, lead author of the study and Royal Society University Research Fellow in the Department of Physics at Imperial College London.

"It's surprising, because you wouldn't expect that if you lost a quarter of the beads from an abacus that it would still be useful."

Traditional computers use bits for computation, which exist either as ones or zeros. Quantum bits, or qbits, use a quality called superposition to operate in both states simultaneously, dramatically increasing computing power per density for certain tasks.

As the number of qbits a system can handle increases, the power increases further, since two qbit systems can process four streams of calculation, rising to eight for three qbits and upwards exponentially.

However, current systems are limited as they are prone to errors when photons, atoms or ions leak out of the system and data is lost.

The new paper suggests that mapping the position of the lost data without affecting the rest of the information is possible, and can increase fault tolerance by two orders of magnitude.

IBM is making a major research push into quantum computing, and scientists have already succeeded in storing information at an atomic level and building functional two-qbit quantum computers. This paper, if proven, will increase the ease of building further systems.

"We are still some way off knowing what the true potential of a quantum computer might be," said Barrett.

"They may not necessarily be better for everything, but we just don't know. They may be better for very specific things that we find impossible now."