Professor Joseph Bardin (principal investigator) of the Electrical and Computer Engineering Department at UMass Amherst and College of Engineering and Dean Sanjay Raman (co-principal investigator) have received a $500,000 grant from the Defense Advanced Research Projects Agency (DARPA), administered by the Office of Naval Research. The title of this DARPA project is “Cryogenic T-MUSIC Circuits for Quantum Computing.” T-MUSIC is a technology that combines advanced silicon-germanium with advanced CMOS to enable ultra-wide bandwidth and to establish a significant advantage over standard CMOS technologies. The team’s research will quantify the cryogenic noise performance of nanometer CMOS and silicon germanium BiCMOS technologies as a function of operating temperature, device size, and power consumption. The two researchers and their students will employ the resulting knowledge to implement state-of-the-art, cryogenic, low-noise-amplifier circuits.
The potential applications of Bardin’s DARPA research could have profound impacts on quantum computing, radio astronomy, deep space communications, remote sensing, and other technologies.
Bardin heads the UMass Quantum RF Group. “We perform basic research on CMOS and BiCMOS integrated electronics to control and measure quantum devices such as quantum bits, single photon detectors, and terahertz radiation mixers,” says Bardin about his lab. “A common theme is that our devices are optimized to work at very low temperatures, often in the range of four to 20 degrees above absolute zero.”
As Bardin describes the background of his DARPA research, running a quantum processor requires a lot of classical (normal) electronics. One particularly challenging aspect is to measure the state of the “qubit,” or quantum bit, which is the basic unit of quantum information. This measurement is so challenging because a receiver system with sensitivity approaching the limits imposed by quantum mechanics is required.
“A critical component in this measurement apparatus,” says Bardin, “is a cryogenically cooled low-noise amplifier (cooled to 4K).”
Typically, such amplifiers are implemented using indium phosphide transistors, which are costly and hard to fabricate.
“In this project,” explains Bardin, “we are investigating the feasibility of achieving similar performance [to indium phosphide transistors] using CMOS transistors, such as those found in central processing unit cores and cell phones.”
The project will undertake three primary goals: to develop an improved understanding of the cryogenic noise performance of nanometer CMOS technologies; to quantify the advantage of T-MUSIC technologies over standard CMOS technologies for use in quantum readout applications; and to demonstrate state-of-the-art cryogenic noise performance using T-MUSIC technology.
Using the models developed from these last two goals, Bardin says, “we will design cryogenic, low-noise-amplifier integrated circuits in the base foundry and T-MUSIC technologies, optimized to approach the fundamental limits of noise performance and power dissipation for each technology.”
Bardin explains that the new models being developed will provide physical insight into the fundamental device properties and, as such, “will provide a powerful tool to understand the cryogenic noise properties of each device.”
In summation, says Bardin, “We believe that the knowledge generated will have impact in microwave applications beyond quantum computing, such as radio astronomy, deep space communications, and remote sensing.” (November 2020)