Preventing information loss in quantum computing is a critical challenge being worked on by physicists and researchers in the field. This challenge is closely related to fundamental quantum mechanics principles, and it is critical to ensuring the reliability and scalability of quantum computers. Nothing exists in a vacuum, but physicists often wish it didn’t. Things would be a lot easier if scientists could completely isolate the systems they study from the outside world.
Consider quantum computing. It’s a field that has already attracted billions of dollars in funding from tech investors and industry titans like IBM, Google, and Microsoft. However, even the smallest vibrations from the outside world can cause a quantum system to lose information. For example, if light has enough energy to jiggle the atoms within a quantum processor chip, it can cause information leaks.
“Everyone is really excited about building quantum computers to answer really hard and important questions,” said Joe Kitzman, a doctoral student at Michigan State. “However, vibrational excitations can seriously destabilize a quantum processor.”
But, with new research published in the journal Nature Communications, Kitzman and his colleagues are showing that these vibrations need not be a hindrance. In fact, they could benefit quantum technology.
Everyone is really excited about building quantum computers to answer really hard and important questions. However, vibrational excitations can seriously destabilize a quantum processor.
Joe Kitzman
“If we can understand how the vibrations couple with our system, we can use that as a resource and a tool for creating and stabilizing some types of quantum states,” Kitzman said.
What that means is that researchers can use these results to help mitigate information lost by quantum bits, or qubits (pronounced “q bits”).
Traditional computers rely on simple binary logic. Bits encode data by assuming one of two distinct possible states, commonly denoted as zero or one. Qubits, on the other hand, are more adaptable and can exist in both zero and one states.
Although this may appear to be cheating, it is perfectly legal under quantum mechanics. Nonetheless, this feature should provide quantum computers with significant advantages over conventional computers for a variety of problems in science, finance, and cybersecurity. Aside from its implications for quantum technology, the MSU-led team’s report lays the groundwork for future experiments to better understand quantum systems in general.
“Ideally, you want to separate your system from the environment, but the environment is always there,” said Johannes Pollanen, the Jerry Cowen Endowed Chair of Physics in the MSU Department of Physics and Astronomy. “It’s almost like junk you don’t want to deal with, but you can learn all kinds of cool stuff about the quantum world when you do.”
Pollanen also directs the College of Natural Science’s Laboratory for Hybrid Quantum Systems, which Kitzman is a member of. The team built a system consisting of a superconducting qubit and surface acoustic wave resonators for the experiments led by Pollanen and Kitzman.
These qubits are one of the most popular among companies working on quantum computers. Mechanical resonators are used in many modern communications devices, such as cell phones and garage door openers, and researchers like Pollanen are now putting them to use in emerging quantum technology.
The researchers’ resonators enabled them to tune the vibrations felt by qubits and understand how the mechanical interaction between the two affected the fidelity of quantum information.
“We’re creating a paradigm system to understand how this information is scrambled,” Pollanen explained. “In this case, we have control over the environment, specifically the mechanical vibrations in the resonator and the qubit.” “You can use your understanding of how these environmental losses affect the system to your advantage,” Kitzman said. “The first step toward solving a problem is understanding it.”
