Hot Qubits Could Deliver a Quantum Computing Breakthrough

  • New “hot qubits” require less cooling and operate at 10 times the temperature of existing projects.
  • The qubits are also built on silicon chips that could more easily be manufactured at scale.
  • Quantum computers are a decade away from achieving their fabled amount of power.

Researchers in Australia have brought quantum computing up to a bewildering 1.5 Kelvin, which may not sound like much until you consider existing technologies require supercooling to almost absolute zero. These scientists say they can quantum compute in an environment 10 times warmer that costs millions less in expensive supercooling equipment.

In the most common form of quantum computing research, scientists use qubits—quantum bits, which are often a single atom of an element with a carefully controlled electron—that must be cooled, ideally, to absolute zero to achieve superconductivity. Absolute zero is impossible, but scientists can get very, very close, and they’re getting slightly even closer all the time.

Each new step costs more money, and often more lead time, for the supercooled tech to get down to temperature. At Sydney’s University of New South Wales (UNSW), researchers have reframed the qubit question in order to make a different paradigm. On a relatively traditional silicon chip, pairs of quantum dots, which are artificial atoms that take the form of microscopic crystals, are arranged and combined with nano-scale magnets to help electrons zoom back and forth.

A second group developed a very similar idea at the same time, in a kind of convergent evolution of quantum computing research. The first and second papers, published simultaneously in Nature, both represent results on an underlying silicon technology UNSW says it developed in 2014.

Using an almost consumer-ready silicon chip means the qubits can be manufactured through established factory channels. While the temperature is the big breakthrough here, the production-friendly tech is also a huge advantage.

Cooling a traditional quantum computer to near absolute zero is already costly, but that’s just the beginning. “Every qubit pair added to the system increases the total heat generated, and added heat leads to errors,” lead researcher Andrew Dzurak said in a statement. “That’s primarily why current designs need to be kept so close to absolute zero.”

It’s also why quantum computers are still so tiny. The cheapest desktop PC we could find on a leading consumer electronics site has an Intel Celeron processor (yes, really!), and this 22-year-old CPU technology could hold several entire quantum computers in just a single container of bits passing through in a fraction of a second. For quantum computers to really both surpass traditional CPUs and reach their promised potential, they need to get huge compared to what researchers are putting together today.

From UNSW’s statement:

“The unit cell developed by Dzurak’s team comprises two qubits confined in a pair of quantum dots embedded in silicon. The result, scaled up, can be manufactured using existing silicon chip factories, and would operate without the need for multi-million-dollar cooling. A quantum computer that is able to perform the complex calculations needed to design new medicines, for example, will require millions of qubit pairs, and is generally accepted to be at least a decade away.”
Turning a handful of bits into millions is daunting—but it’s much less so at 1.5 Kelvin than it is at absolute zero. And during the next 10 years, many more barriers are likely to come down.