Chinese and American scientists use graphene system to explore new ways of processing quantum information

Xinhua News Agency, Hefei, January 28 The reporter learned from the University of Science and Technology of China that Guo Guoping, a professor at the university, Deng Guangwei, an associate researcher, and Tian Lin, a professor at the University of California, Merced, The pioneer of introducing the third harmonic oscillator as the phonon cavity mode has successfully realized long-range strong coupling and created the conditions for storing and transmitting quantum information using the phonon mode as the carrier. International Journal of Nature 1 The result was released on the 26th.

The nanometer harmonic oscillator has the advantages of small size, good stability and high quality factor, and is an excellent carrier for information storage, manipulation and transmission. Both classical and quantum information can be encoded in the phonon state of the harmonic oscillator, and the phonon state can also be used In order to realize this scheme, one of the major challenges is how to realize tunable phonon interaction over long distances. In recent years, the international academic community has tried to use the optical cavity or the superconducting microwave cavity as the medium for transmitting coupling. However, due to the difference in frequency Huge and coupling strength is usually small, it is difficult to achieve a strong coupling range.

In response to this challenge, Guo Guoping's research group proposed the idea of ​​using the resonator itself as a phonon cavity cavity instead of a cavity or a microwave cavity, and designed and prepared a series structure of three graphene nanometer resonator. In this device, The resonance frequency of each resonator can be greatly adjusted by the metal electrode at the bottom of each resonator.It has been experimentally proved that the adjacent resonators can reach the strong coupling region in the series structure and when the frequency of the intermediate resonator is adjusted to be close to both ends of the resonance When the resonant frequency of the son, there is a great mode splitting between the two resonators, and the splitting value can be widely controlled by controlling the frequency of the intermediate harmonic oscillator.

Using the theoretical analysis of optical Raman process, the research team obtained the equivalent coupling strength of harmonic oscillators at both ends and their relationship with the detuning volume. The experimental results show that the measured equivalent coupling is in good agreement with the theoretical results.

According to reports, the experiment for the first time to achieve a non-neighbors in the graphene nanoshelf resonator coupling, for the study of mechanical and electrical harmonic oscillator has an important impetus for the phonon mode as a carrier for storage and transmission of quantum information to create the conditions.