Making the unreal real in quantum computing
Making the unreal real in quantum computing lead image
For universal quantum computation, achieving a large number of qubits is crucial but challenging. Instead, increasing the qubits’ coherence times decreases the needed amount of qubits. Twenty-five years ago, scientists theorized that making qubits from electrons floating above liquid helium would enable long coherence times. Recently, a floating-electron-on-solid-neon qubit set a world record of 100 microseconds coherence time for charge qubits, and a spin qubit is predicted to reach around 1 second.
Jennings et al. reviewed floating-electron-based qubits, including experiments and proposals on how they can be realized using helium or neon. The review caters to anyone interested in quantum computing, especially those who are interested in alternative methods.
“Considering alternative possibilities to build a quantum computer is important just by itself, as current technologies may not pan out or we might need a hybrid system,” said author Asher Jennings. “We want to show that electron-on-helium qubits are not unrealistic.”
Many theories borrow ideas from other, more developed qubit systems and scientific fields.
For example, author Xianjing Zhou noted, the scientists discovering the world-record-setting floating-electron-based neon qubit leveraged their knowledge of superconductor physics to control and read the qubit.
“Technologies researchers are trying to use are not very distant from those used for other qubits,” Jennings said. “A reader might already have some device or technique that could be applied to electrons on helium or neon, and it is not difficult to cover something with liquid helium or solid neon.”
The authors hope their work inspires scientists to think of ideas to realize floating-electron-based qubits.
Source: “Quantum computing using floating electrons on cryogenic substrates: Potential And Challenges,” by A. Jennings, X. Zhou, I. Grytsenko, and E. Kawakami, Applied Physics Letters (2024). The article can be accessed at https://doi.org/10.1063/5.0179700 .
