Quantum Computing Method Paves Way for Different Algorithms and Experiments

A new and more efficient computing technique has been discovered by scientists by combining the reliability of a traditional computer with the power of a quantum system.

Video Credit: University of Waterloo.

This latest computing technique paves the way for different experiments and algorithms that bring quantum scientists one step closer to near-term applications and discoveries of the technology.

In the future, quantum computers could be used in a wide variety of applications including helping to remove carbon dioxide from the atmosphere, developing artificial limbs and designing more efficient pharmaceuticals.

Christine Muschik, Principal Investigator, Institute for Quantum Computing, University of Waterloo

Muschik is also a faculty member in physics and astronomy at the University of Waterloo.

The researchers from the Institute for Quantum Computing (IQC), in association with the University of Innsbruck, were the first to suggest this measurement-based method in a feedback loop with a standard computer, thus identifying a new way to address complex computing issues. Their technique is resource-efficient and so can use small quantum states since they are customized to certain kinds of issues.

Hybrid computing, in which the processor of a regular computer and a quantum co-processor are combined into a feedback loop, provides scientists with a flexible and stronger method instead of trying to use a quantum computer alone.

While scientists are presently constructing hybrid computers based on quantum gates, Muschik’s research group was more interested in the quantum computations that could be performed without using gates. The researchers also developed an algorithm where a hybrid quantum-classical computation was performed by making a series of measurements on an entwined quantum state.

The researcher's theoretical study bodes well for both quantum software developers and experimentalists because it offers a new way of visualizing optimization algorithms. The algorithm provides high error tolerance, which is often a problem in quantum systems and operates for a broad range of quantum systems, such as photonic quantum co-processors.

Hybrid computing is an innovative frontier in near-term quantum applications. By eliminating the dependence on quantum gates, Muschik and her research group have prevented the difficulties associated with fragile and finicky resources and instead, by applying entangled quantum states, they hope to develop feedback loops that can be customized to the datasets that are being researched by the computers in a more efficient way.

Quantum computers have the potential to solve problems that supercomputers can’t, but they are still experimental and fragile.

Christine Muschik, Principal Investigator, Institute for Quantum Computing, University of Waterloo

The study titled, “A measurement-based variational quantum eigensolver,” which explains the researchers’ work, was recently published in the Physical Review Letters journal. The project was financially supported by CIFAR.

Journal Reference:

Ferguson, R. R., et al. (2021) Measurement-Based Variational Quantum Eigensolver. Physical Review Letters. doi.org/10.1103/PhysRevLett.126.220501.