A new ultra-cold microwave source controlling quantum computing was successfully developed

IT House December 13 -- A study published last week in Nature Electronics showed that a consortium of researchers from Finland's Aalto University, VTT and IQM has designed a new microwave source that can replace the existing massive control system that hinders the scalability of quantum computers.

According to reports, this kind of circuit can produce the high-quality microwave signal required to control the quantum computer at a temperature close to absolute zero. This is a critical step in moving the control system closer to the quantum processor, which could greatly increase the number of qubits in the processor.

"We have built an accurate microwave source that can operate at the same low temperature as a quantum processor, around -273°C," said team leader Mikko M tt nen, a professor at Aalto University and the VTT Technology Research Centre in Finland, co-founder and chief scientist at IQM.

The new microwave source is an on-chip device that can be integrated with a quantum processor. It measures about a millimeter in size and does not require the connection of high-frequency control cables at different temperatures. Using such a low-power, low-temperature microwave source, a smaller cryostat can be used while still increasing the number of qubits in the processor.

"Our device produces 100 times more power than the previous version, enough to control qubits and perform quantum logic operations," M tt nen said. It produces a very precise sine wave that oscillates more than a billion times per second. As a result, qubit errors from microwave sources rarely occur, which is important when implementing precise quantum logic operations.

However, continuous wave microwave sources, such as those produced by the device, cannot be used to control qubits as is. First, the microwave must be shaped into a pulse. The team is currently developing ways to quickly turn microwave sources on and off.

IT House understands that even without pulse-generating switching solutions, high-efficiency, low-noise, low-temperature microwave sources can be used for a range of quantum technologies, such as quantum sensors.

"In addition to quantum computers and sensors, microwave sources can also serve as clocks for other electronic devices." M tt nen explains that it allows different devices to maintain the same rhythm, allowing them to manipulate several different qubits in an instant of the time they need.

The theoretical analysis and preliminary design of the study was done by Juha Hassel et al. of VTT. Hassel is currently the head of engineering and development for IQM Quantum Computers, the leader in pan-European quantum computers.

The device was then manufactured at VTT and operated by Chengyu Yan, a postdoctoral researcher at Aalto University, and his colleagues using the OtaNano research infrastructure.

In addition, it includes Yan Xian, associate professor of Huazhong University of Science and Technology, and Yan Chengyu, who appeared among the authors of the articles.