 |
Professor Chen Guangcan, a professor at the University of Science and Technology of China and a key laboratory of quantum information at the Chinese Academy of Sciences, has successfully developed a graphene quantum chip unit that can be integrated. The laboratory solid-state quantum chip group Professor Guo Guoping and his collaborators successfully achieved the coupling of graphene quantum dot qubits and superconducting microwave cavity quantum data bus. The phase coherence time of graphene qubits and its unique four-fold measurement were first determined. Cycle characteristics, and for the first time in the international implementation of the long-range coupling of two graphene qubits, to achieve an integrated quantum chip has taken an important step. The series was published in the Phys. Rev. Lett. 115, 126804 (2015) and Nano Lett. DOI: 10.1021/acs.nanolett.5b02400(2015). Deng Guangwei is the first author of this series of work.
Graphene, a new flexible semiconductor material, is widely regarded as an important carrier for next-generation semiconductor devices. The elimination of the effects of spin-orbit coupling and net nuclear spin also provides an attractive prospect for the application of graphene in quantum chips. However, the relativistic properties and zero-gap energy band structure of such single-layer carbon atom material carriers also pose a high challenge to the construction of graphene-based qubits. In addition, the highly integrated nature of the quantum chips used in practice requires that the constructed qubit be coupled to a non-local quantum data bus.
After Guo Guoping’s research group proposed the introduction of a superconducting cavity into a semiconductor quantum chip as a quantum data bus [Phys. Rev. Lett. 101, 230501 (2008)] in 2008, after nearly 7 years of efforts, it has captured graphene. Fully controlled single and double quantum dot preparation, design and construction of graphene qubits, and other series of difficulties, developed a new type of superconducting microwave resonator with independent intellectual property rights, and finally realized a composite structure of superconducting microwave cavity and graphene qubits. . Experimental tests show that the coupling strength of the novel superconducting quantum data bus and graphene qubits reaches 30 MHz, which will be of great significance in the future large-scale integrated quantum chip architecture.
The research group used the microwave detection technology on the graphene and superconducting composite structure to determine the phase coherence time of the graphene quantum dot bit for the first time in the world, and further discovered that the graphene quantum coherence time and the number of carriers in the quantum dot have The unique quadruple cycle characteristic provides a new method and new mechanism for the experimental exploration and verification of the basic physics brought about by the quadruple degeneracy of graphene spin and energy valley freedom.
After deeply studying the coupling mechanism between a single qubit and a superconducting cavity, the research team aimed at the problem of long-range coupling of quantum bits, and for the first time successfully achieved two graphene qubits internationally. Long-range coupling, quantum correlation between two qubits measuring 60 microns apart (200 times the size of the quantum dot itself) was measured. Because it was the first two-bit long-range coupling based on superconducting cavity in the quantum dot system, the article immediately after the publication of arXiv (1409.4980) attracted extensive attention from international peers and was published in the papers of Science, PRL and other publications. According to the evaluation, it is of great significance for realizing the quantum entanglement between the long-distance quantum dot bits and eventually implementing the integrated quantum chip in the future.
This work was funded by the Ministry of Science and Technology, the National Natural Science Foundation of China, the Chinese Academy of Sciences and the Ministry of Education.
Pad Painters,Paint Pad Edging Tool,Pro Pad Painters,Pro Corner Paint Pad
Ningbo Beilun Gelei Plastic Parts Co.,Ltd , https://www.paintwelltools.com