Researchers develop data bus for quantum computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation, however, because quantum systems are very sensitive to environmental noise. Although systems can be protected from noise in principle, researchers have been able to build only small prototypes of quantum computers experimentally.

One way to reduce the error rate is by encoding quantum information not in one single quantum particle but in several quantum objects. These logical quantum bits or qubits are more robust against noise. In the last few years, theoretical physicists have developed a whole range of error correction codes and optimized them for specific tasks. Physicists Hendrik Poulsen Nautrup and Hans Briegel from the Institute of Theoretical Physics of the University of Innsbruck and Nicolai Friis, now at the Instituteof Quantum Optics and Quantum Information in Vienna, have found a technique to transfer quantum information between systems that are encoded differently.