A new technique can reset bits in quantum computers highly effectively, a critical task for successful quantum computing, according to the US National Institute of Standards and Technology (NIST). The technique uses heat flow between different sections of a refrigerator to reset qubits, the first time this method has been harnessed for a practical purpose.
The method could address one of the main issues confronting quantum computer designers: the need to keep the bits in a superconducting quantum processor free of errors and ready to perform calculations whenever necessary. Qubits are notoriously sensitive to heat and radiation, which can spoil their calculations just as stray chalk marks might make the numeral 1 look like a 7.
“Erasing” these qubits after a calculation involves cooling them to a fraction of a degree above absolute zero and then keeping them there. The team’s method is not only more effective than other state-of-the-art methods for erasing the qubit chalkboard because of the lower temperatures it achieves, but it also achieves them in a novel way — powering the eraser using heat flowing between two parts of the refrigerator that keeps the computer cold. This approach could prove itself useful in other ways.
“In a quantum computer, initial errors can compound as the calculation proceeds,” explained quantum physicist Aamir Ali of Chalmers University of Technology in Sweden, where the team’s experimental work was conducted. “The more you can get rid of them at the outset, the more effort you will save later.”
“We think this approach will pave the way for more reliable quantum computing,” Ali said. “It’s hard to manage errors in quantum computers right now. Beginning closer to the ground state will compound into fewer errors you’d need to correct down the line, reducing errors before they occur.”