Scientists just found a way to make quantum states last 10,000 times longer

One of the major challenges in taking quantum technology from potential to reality is to make ultra-delicate quantum states last longer than a few milliseconds – and scientists have just raised the bar by a factor of about 10,000.

They did this by tackling what is called decoherence: it is the disturbance of surrounding noise caused by vibrations, temperature fluctuations and interference from electromagnetic fields that can very easily break a quantum state,

“With this approach, we are not trying to eliminate noise in the surroundings,” explains quantum engineer Kevin Miao of the University of Chicago. “Instead, we trick the system into believing that it is not experiencing noise.”

By applying a DC magnetic field to a type of quantum system called a solid-state qubit, in addition to the standard electromagnetic pulses required to keep such a system under control, the team was able to “ eliminate ” unnecessary noise.

Researchers liken it to a merry-go-round – the faster you go, the less able you are to hear the noise of your surroundings, because everything merges into one. In this case, the rotating electrons are the merry-go-round.

Using the new approach, the semiconductor qubit system was able to remain stable for 22 milliseconds – four orders of magnitude or 10,000 times longer than previous efforts, although still less than a tenth of a blink of an eye. eye.

Researcher Kevin Miao. (David Awschalom)

The qubit is the quantum version of a standard computer bit, but instead of only being able to code 1s and 0s, it can achieve a state of superposition that makes it much more powerful.

Decoherence is a kind of nemesis for quantum scientists. Other attempts to reduce background noise have been to isolate quantum systems perfectly – which is technically very difficult – or to use the purest materials possible to build them – which can quickly become expensive.

The new approach might offer a more practical solution.

“This breakthrough lays the groundwork for exciting new avenues of research in quantum science,” says physicist David Awschalom, of the Argonne National Laboratory in the United States.

“The wide applicability of this discovery, coupled with a remarkably simple implementation, allows this robust consistency to impact many aspects of quantum engineering. It opens up new research opportunities previously deemed unfeasible.

Researchers say it should work in other areas of quantum physics as well, without needing to adapt it too much – superconducting quantum bits and molecular quantum systems, for example, are other systems that could benefit. . We’re talking about everything from supercomputers to the hackable internet, here.

Our quantum future is still a long way off, but every scientific step forward brings us one step closer.

“There are a lot of candidates for quantum technology who have been sidelined because they couldn’t maintain quantum coherence for long periods of time,” Miao says. “These could be re-evaluated now that we have this way of massively improving consistency.”

“The best part is, it’s incredibly easy to do. The science behind it is complex, but the logistics of adding an alternating magnetic field are very simple.”

The research was published in Science.