New quantum computers can operate at higher temperatures

Silicon chips raise hopes for scaling up devices to millions of quantum bits

Researchers from QuTech work

Quantum computers are warming up. Researchers from QuTech work on a silicon-based quantum computer that operates at higher temperatures than most other types.

Wouterslitsfotografie for QuTech.

Quantum computing’s deep freeze is beginning to thaw.

Computers that harness quantum physics could trump standard computers on certain types of calculations. But the machines typically work only at temperatures tiny fractions of a degree above absolute zero. Now, two teams of physicists report that they’ve created silicon-based quantum computers that work under warmer conditions.

The devices operate more than a degree above absolute zero, the scientists report in two papers published in the April 16 Nature. Although still chilly, that temperature is much easier to achieve than the approximately 10 millikelvin (0.01 degrees above absolute zero) temperatures typical of a popular type of quantum computer based on superconductors, materials which transmit electricity without resistance.

Current quantum computers top out at around 50 quantum bits, but scientists expect quantum computers will need millions of these qubits to perform some tasks. So scientists are working to scale them up.

Simplifying the cooling process could help the computers grow. That’s because extremely cold quantum computers have an additional complication. The electronic components required to control the qubits don’t work under such chilly conditions, and need to be kept in a warmer location and connected to the quantum chip with wiring. That wiring would become unreasonably complex as quantum computers scale up.  But with quantum computers that operate at these warmer temperatures, the qubits and electronics could be joined together, akin to the integrated circuits that helped make conventional computers increasingly powerful and ubiquitous.

Created by teams including researchers from the University of New South Wales in Australia and QuTech in Delft, the Netherlands, the warmer quantum computers are made with silicon. That material is used in standard computer chips, so manufacturers are already skilled with it (SN: 2/14/18). That could also speed quantum computers’ scale-up.

Physics writer Emily Conover has a Ph.D. in physics from the University of Chicago. She is a two-time winner of the D.C. Science Writers’ Association Newsbrief award.

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