By Heather Hamilton, contributing writer
Researchers from Aalto University in Finland have developed a way to cool quantum computers, an ongoing issue in their development. According to Phys.org, quantum computers differ from regular computers in that they use quantum bits, called qubits. The bits in a normal computer are zeros or ones and enact sequence logical, whereas qubits exist in both states, allowing calculations to take place in parallel. This allows an entire new realm of computation to take place that can delve deeper into logistics, health screen, and even artificial intelligence. At the same time, their versatility makes them sensitive to external factors. If they get too hot, they are not initialized because they’re switching between different states too frequently.
In an interview with IFLScience, lead researcher Mikko Möttönen said, “One of the basic criteria that a working quantum computer must satisfy is that there has to be a way to accurately initialize its memory. In practice, this means that we must be able to accurately take the quantum bits in their ground state.”
Of course, this means a temperature of absolute zero temperature, though close will do. Enter Möttönen and his team of researchers with a refrigerator for quantum computers. The study began with the idea that something can be cooled down with radiation. By using quantum mega-microwave to surround superconducting devices, which the researchers used in place of qubits, with electrons carrying just a bit less energy than necessary to quantum phase-shift (tunnel) through a nanoscale insulator beside their qubits.
When the electrons interact with the qubit stand-in, they have a variety of interactions, which includes the natural stealing of energy. So, the energy is stolen, the electron tunnels through the insulator and is then stranded because it now lacks the energy to get back. Slowly, it is cooled by energy theft.
“With our new refrigerator, we think that is should be possible to reset qubits very accurately to their ground states in just a couple of tens of nanoseconds,” Möttönen said.
The nanoscale refrigerator makes quantum computers more reliable and powerful. Kuan Yen Tan, a postdoctoral researchers in Möttönen’s group of researchers, has worked on the cooling device for five years and is pleased that it is now functional. “Our refrigerator keeps quanta in order,” Mikko Möttönen says.
Currently quantum computers exist in limited availability, in part because they’re difficult to cool. According to Inverse, D-Wave Systems cools quantum devices with liquid helium, which is very expensive and is accompanied by a host of additional problems. The refrigerators are complicated and costly, and also prone to breakdowns. An efficient cooling process could reduce the price of chips and allow engineering to include more qubits in each processor and make quantum computers a reality for everyday users.
Still, there is work to be done. Möttönen’s group will now work toward cooling quantum bits in addition to resonators. They’d also like to lower the minimum temperature achievable with refrigerator,and make its on/off switch function with more speed.
“Thus far we have also only shown that we can turn the cooling on and off but not how fast,” Möttönen said. “We want to be able to do this in nanosecond timescales for qubits. Again, we do not see any obstacles here and are currently working on an experiment showing that the fridge is very fast as well.”
Sources: Nature Communications, Phys.org, IFLScience, Inverse
Image Source: Wikimedia
Advertisement
Learn more about Electronic Products Magazine
