UNN scientists come up with new method to control spin qubit
Lobachevsky University physicists have developed a model for a new scheme of semiconductor spin qubit - one of the most promising particles for creating quantum computers. The scientists have discovered patterns that make it possible to adjust the acceleration of quantum operations and integrate them with other computing systems.
This approach makes it possible to do without expensive terahertz equipment and to control the qubit with available microwave devices at frequencies of 1010 - 1011 Hz. Thus, it can increase the speed of quantum operations and reduce the cost of experiments.
A spin qubit is a particle that provides information transfer due to its own magnetic moment (spin) under the influence of a strong magnetic field. Using a mathematical model, UNN scientists have calculated the conditions under which the particle accelerates as it moves between neighbouring quantum dots. By controlling the amplitude of the external field, it is possible to accelerate the particle's rotation.
"While developing the model, we found some regions of controlling parameters of the system and the fields, when the process of spin flipping is significantly accelerated if the particle tunnels from one quantum dot to another, in the same chip block. This second region serves as a kind of "amplifier" for the spin flip process in a periodic electric field", explained the author of the study, Associate Professor of the UNN Department of Theoretical Physics Denis Khomitsky.
Fast quantum operations open the way to the development of efficient and error-resistant quantum computing schemes. The method allows flexible tuning of artificial quantum systems by the external field without using additional equipment and modification of their design schemes. In the future, this will simplify the experimental observation of the spin qubit behaviour.
"The new approach will provide a tool for processing quantum information, studying qubit states and performing fast and high-precision quantum operations," said Marina Bastrakova, Head of the Research Laboratory of Nanostructures Theory at the UNN Physics and Technology Research Institute (PTRI).
The study was carried out by researchers from the Department of Theoretical Physics of the UNN Faculty of Physics, the Laboratory of Nanostructures Theory at PTRI, and the UNN Institute of Information Technology, Mathematics and Mechanics under the state assignment of the Ministry of Science and Higher Education of the Russian Federation as part of the grant project "Quantum Structures for Quantum Technologies". The results of the study were published in the leading international journal Physical Review B.
