Researchers have broken through a major barrier on the road to building powerful quantum computers. Current quantum computers struggle to store data when they aren’t frozen to incredibly cold temperatures — a state that’s quite impractical for eventual consumer devices — but researchers have now managed to store quantum data at room temperature for a substantial amount of time: thirty-nine minutes, dramatically lapping the previous record of just two seconds.
From two seconds to thirty-nine minutes
The research was led by a team at Canada’s Simon Fraser University, and is described in a paper published today in Science. Researchers say they were able to bring the bits of quantum data — what are known as qubits — from their frozen state at -452.2 degrees Fahrenheit up to a warm 77 degrees Fahrenheit without destroying all of them. The qubits could even be read later on.
To create such long-lasting qubits, the researchers began with a piece of silicon and introduced impurities into it, including phosphorus and other elements. Around 10 billion phosphorus ions were placed in the silicon, with each of their nuclei used to store binary data: either a 1, a 0, or both at the same time, thanks to a quantum property known as a superposition. In this case, all of the qubits were held in a superposition — an ability that will be fundamental to the success of quantum computing by allowing a single qubit to perform multiple functions at once.
Though surviving for 39 minutes may not sound like very long, it only requires one-hundred-thousandth of a second to perform an operation on a single qubit. So theoretically, over 20 million operations could be performed before the qubits’ data decayed by 1 percent. "Having such robust, as well as long-lived, qubits could prove very helpful for anyone trying to build a quantum computer," Stephanie Simmons, a co-author of the paper, says in a statement.
Qubits still have to be refrozen before being read
But while storing quibits at room temperature is moving closer to reality, there’s still a ways to go. Researchers still needed to refreeze the qubits to their original temperature before their data could be read. And not all of the qubits survived: only 37 percent made it through the process.
Importantly though, it wasn’t the warm temperatures that destroyed the other qubits’ data. The 63 percent that died did so early in the storage process — before the freezing was even complete — because of issues that remain with that early step. That means that every remaining qubit made it through the unfreezing and refreezing process intact.
One of the next large hurdles that the researchers identify will be diversifying what data the quibits are holding. For the experiment, all of the qubits stored the same data — either all 1s or all 0s — but to run calculations or store anything complex, they’ll have to include a mixture of 1s and 0s just like traditional storage methods do. That may not be right around the corner, but it was hardly more than a year ago that qubits couldn’t handle warmth for more than two seconds either.