One of the challenges to realizing the full potential of quantum computing is figuring out how millions of qubits – those quantum equivalents of the classical bits that store ones or zeros in conventional computers – can work together.
Scientists at the University of Sussex in the UK have now succeeded in transporting qubits directly between two quantum computer microchips, at speeds and accuracies well above anything previously seen with this technology.
This shows that quantum computers can be scaled beyond the physical limits of a microchip, a crucial factor when dealing with potentially millions of qubits in the same machine. Universal Quantum, a startup spun out of the University of Sussex, will continue to develop the technology.
Researchers Winfried Hensinger and Sebastian Weidt with their quantum computer prototype. (University of Sussex)
“The team has demonstrated fast and coherent ion transfer using quantum matter interconnects,” says quantum scientist Mariam Akhtar. Akhtar led research on the prototype while she was at the University of Sussex.
“This experiment validates the unique architecture that Universal Quantum has developed – and offers an exciting path to truly large-scale quantum computing.”
The researchers used a special technique they call UQConnect to make the transfers, using an electric field to transport qubits. This means that microchips could be put together like pieces of a jigsaw puzzle to build quantum computers.
Researcher Mariam Akhtar with the control panel of the quantum computer. (University of Sussex)
While it is notoriously difficult to keep and move qubits, the team achieved a 99.999993 percent success rate and a connection rate of 2,424 links per second. There is the possibility of connecting hundreds or even thousands of quantum computer microchips in this way with minimal loss of data or fidelity.
There’s more than one way to build a quantum microchip: in this case, the architecture used trapped atomic ions as qubits for the best stability and reliability, and charge-coupled circuitry for superior electrical charge transfer.
“As quantum computers grow, we will eventually be constrained by the size of the microchip, which limits the number of quantum bits such a chip can hold,” says quantum scientist Winfried Hensinger of the University of Sussex.
“Thus, we knew that a modular approach is key to making quantum computing powerful enough to solve breakthrough industrial problems.”
Some of the purposes that quantum computing could eventually be used for include the development of new materials, research into drug treatments, cybersecurity improvements, and climate change modeling.
Although quantum computers exist today, they are limited in scope compared to what they might later become – they are more research projects than machines that can be practically used and programmed.
Breakthroughs like the one we’ve reported here are pushing us to realize the full potential of quantum computing, and developing ways to harness millions of qubits is an integral part of that.
“These exciting results demonstrate the remarkable potential of Universal Quantum’s quantum computers to become powerful enough to unlock the many life-changing applications of quantum computing,” says quantum scientist Sebastian Weidt of the University of Sussex.
The research was published in Nature Communications.