The U.S. Department of Energy renewed a $125 million grant to the Fermi National Accelerator Laboratory's Superconducting Quantum Materials and Systems Center. University of Arizona College of Engineering researchers will play a key role in the project to accelerate quantum technology over the next five years. 

Bane Vasić, the Kenneth Von Behren Professor of Electrical and Computer Engineering, is the lead on error correction theory at Fermilab. He partnered with electrical and computer engineering assistant professor Narayanan Rengaswamy and assistant researcher professor Nithin Raveendran, along with doctoral student Shantom Borah, to refine codes that minimize errors in quantum computers.

"This grant funding will help us enormously in developing and perfecting these systems," said Vasić. 

Quantum computing is poised to accelerate solutions in machine learning, drug development, data storage, agriculture and cybersecurity.

Catching errors with code

Quantum computers harness properties from subatomic particles like electrons to store and process information faster than classical computers. 

Qubits – microscopic units of information that encode computer data – exploit superposition, where an electron's properties, such as spin, remain undefined until measured. This allows qubits to hold two values simultaneously, unlike classical bits that hold only one. Particles can also be linked through quantum entanglement, so that measuring one determines the other's output. These properties enable quantum computers to solve problems exponentially faster than classical computers.

Qubits are fragile, however. Environmental interference can corrupt them before measurement, causing computational errors. Eliminating noise and correcting errors rank among quantum computing's primary challenges.

As director of the Error Correction Laboratory at the U of A, Vasić and his team develop quantum low-density parity check, or QLDPC, codes and decoding algorithms to detect and correct errors. QLDPC codes help qubits break down complex error correction functions into manageable steps and use fewer qubits than the more popular method of topological codes.

"We aim to develop a system that uses these QLDPC codes," Vasić said. "And our team at the University of Arizona has unique expertise to bring them to reality and enable large-scale quantum computing."

Multidisciplinary approach yields success

As one of the nation's premier particle physics laboratories, Fermilab provides center members a platform to share expertise and technologies. The U of A plays a central role in that effort.

"The SQMS brings together researchers from both the quantum physics and coding theory communities to forge a path towards the vision of universal quantum computing," Vasić said.