Future quantum computers will have the ability to perform calculations that are unthinkable with even the most powerful existing supercomputer. But before getting there, there are many barriers to overcome. One of them is error-correcting.
Researchers at ETH Zurich have shown, for the first time, that it is possible to automatically correct errors in quantum systems and this can be done so quickly and continuously that results of quantum operations can be used in practice. The findings were uploaded on the repository ArXiv and they await peer review.
“The demonstration that errors in a quantum computer working with quantum bits (qubits) can be corrected quickly and repeatedly is a breakthrough on the road to building a practical quantum computer,” co-author Andreas Wallraff, Director of the Quantum Center at ETH Zurich, said in a statement.
Since these new computers are based on quantum systems, their processing unit is very delicate and it has to be kept at very low temperatures, just over absolute zero. Processes that can help deal with errors are being investigated. The system looked at in this work employs 17 qubits and operates at a temperature of just 0.01 Kelvin. That’s a fraction of a degree above absolute zero.
At that temperature, the qubits are superconducting, electricity flows through them with no resistance. Nine of the 17 qubits are organized on a square array, creating a three-by-three lattice. They are the logical unit. All the computation is done by these nine elements.
The remaining eight serve as a control and they are tasked to detect errors in the system. If the qubits detect them, the system can then correct itself. Thanks to these, disturbances that alter the information in the system can be recognized and accounted for.
“Right now, we’re not correcting the errors directly in the qubits,” explained co-lead author Sebastian Krinner. “But for most arithmetic operations, that’s not even necessary.”
This new research shows that error-correcting is possible and practical but we are not yet at a level where quantum computers can be fault-proof.
“Our demonstration of repeated, fast and high-performance quantum error correction cycles, together with recent advances in ion traps, support our understanding that fault-tolerant quantum computation will be practically realizable,” the team wrote in their paper.
The work is not the only approach trying to deal with error correction. Recently, a new quantum phase has been seen as a possible solution to this problem.
Quantum computers might not be here yet but as new problems arise, scientists around the world rise to the challenge and tackle them.