New tool analyses reliability of quantum computers

New tool analyses reliability of quantum computers

Researchers at the University of Warwick have developed a quantum computer program to detect the presence of leakage. Leakage occurs when information as processed by a quantum computer escapes from positions 0 and 1. The report was published yesterday in the journal Physical Review A, according to PhysOrg.

The new computer program gives users of this promising technology the opportunity to check its reliability without any technical knowledge. The commercial interest in quantum computing is growing, so we wondered how we could determine with certainty that these machines are doing what they should be doing. Quantum computers are ideally made of qubits, but as it turns out in real devices, sometimes they are not qubits at all. In some cases they are qutrits (three positions) or quartz (four positions). Animesh Datta, associate professor of physics, observes that such a problem can damage every next step of your computer processing.

Datta is of the opinion that computer technicians are needed to reduce leakage as much as possible. If quantum computers are going to be widely used in the long run, it is important that a user with no idea of how a quantum computer works, can check whether it is functioning properly. Without technical knowledge or if they get remote access to their computer.

Dimension witnessing

The researchers applied their method using the IBM Q Experience quantum devices, which are accessible via IBM’s public cloud service. They used a technique called dimension witnessing: by repeatedly applying the same operation to the IBM Q platform, the researchers obtained a dataset with results. These could not be explained by a single quantum bit. This required a more complicated, higher-dimensional quantum system. In its own words, the chance that this conclusion comes from mere chance is less than 0.05%.

It’s no small thing to be able to make this conclusion at a distance of a few thousand kilometres. In addition, access to the IBM chip itself was very limited. Although our program only used the allowed single qubit instructions, the dimension witnessing approach was able to show that unwanted states were approached in the components of the transmission circuit. I consider this a victory for any user who wants to investigate the advertised properties of a quantum machine. And then without referring to hardware-specific details, according to researcher George Knee.

Read also: Intel accelerates development quantum bits with new test system

This news article was automatically translated from Dutch to give a head start. All news articles after September 1, 2019 are written in native English and NOT translated. All our background stories are written in native English as well. For more information read our launch article.