Time crystals may make quantum computers more reliable

Ultracold atoms that constantly move in repeating patterns, in a form of matter called a time crystal, could be used to build quantum computers that produce fewer errors.

In conventional computers, printed circuit boards consist of solid materials like plastic. A circuit board made from time crystals would involve thousands of atoms almost as cold as absolute zero, one of the conditions required for quantum phenomena to unfold. Krzysztof Sacha at the Jagiellonian University in Poland and his colleagues developed a mathematical blueprint for such “temporal printed circuit boards”.

The atoms in time crystals always move in recurring patterns, similar to the way atoms in ordinary crystals have a repeating structure. In temporal printed circuit boards, the atoms’ quantum states would execute repeating patterns and encode information in quantum bits, or qubits.

Quantum computers are expected to eventually solve problems that are impossible for conventional computers, but they have mostly not lived up to that promise so far. This is in part because qubits must interact to run calculations, which can degrade their quantum states and the information encoded within them, risking errors.

But the new qubits would not encounter this problem, says Krzysztof Giergiel at Swinburne University of Technology in Australia. He says existing in a time crystal means the qubits would be spread out and always in motion, so each one could more easily cross paths and interact with the others. In fact, connections between distant qubits that would be impossible in other quantum computer designs could be realised relatively easily with the temporal printed circuit boards, says Sacha. This would make it possible to run more complex quantum computer programs and obtain more reliable results.

If these quantum computers can be built, it “would be nothing short of a major breakthrough”, says Samuli Autti at Lancaster University in the UK. Some of the methods researchers will have to use in order to build temporal printed circuit boards have already been tested in other experiments. But using them to conduct actual quantum computations would be completely new, says Biao Huang at the University of Chinese Academy of Sciences.

The researchers are already charging ahead. Hannaford’s team is currently working on making a time crystal from ultracold potassium atoms – the first step towards creating the new quantum computer.