New type of qubits for quantum devices developed at Lobachevsky University
Lobachevsky University physicists have designed a new type of qubits based on artificial atoms, which opens up prospects for developing a semiconductor platform for quantum computing. Such qubits can effectively encode and process quantum information.
For the first time in Russia, researchers have calculated conditions for controlling simultaneously two parameters of a qubit: the charge and the flipped spin, which paves the way to the development of more stable and controllable quantum devices.
“Using the electric field, we control both the charge and the rotation vector of the qubit, which allows us to build more complex but small-sized quantum systems. Designing basic technologies for quantum computing, including hybrid qubits on semiconductor heterostructures, is a priority for the development of Russian nanoelectronics. Implementation of controlled spin-charge qubits with dynamic stabilization of states can be a key step towards producing scalable quantum processors”, said co-author of the study Marina Bastrakova, Associate Professor at the UNN Department of Theoretical Physics.
The study also revealed a previously unknown spin memory effect in hybrid qubits. By controlling the state of quantum particles using the electric field, it is possible to “lock” the qubit at a certain energy level. This effect makes it possible to preserve the quantum state of the particle for a time exceeding the characteristic lifetime of the spin state. This opens new prospects for creating non-volatile electrically controlled quantum memory elements necessary for the development of full-scale quantum computers.
“Any system tends to the minimum of energy, particles go to ever lower levels, so it is almost impossible to fix the desired cubit values for a long time. However, we have managed to do it. In an alternating electric field, we kept the qubit in the state we needed. During this time, it is possible to perform necessary operations in quantum applications”, explained the author of the study Denis Khomitsky, Associate Professor at the UNN Department of Theoretical Physics.
The system is based on gallium arsenide, a widely used semiconductor material with well-studied properties, which in the future will make it possible to scale up the research and integrate the design into various types of quantum devices. In the near future, the scientists will continue studying the spin memory effect, optimize quantum operations in hybrid spin-charge qubit registers and develop methods of quantum error correction, which is necessary for producing quantum processors.
The project was carried out by scientists of the UNN Faculty of Physics with the support of the Ministry of Science and Higher Education of the Russian Federation. The results were published in the prestigious international journal Physical Review B.
