HOME > Research Results > Research Highlights, Key Components of Quantum Information Transmission by Surface Acoustic Waves

Research Highlights, Key Components of Quantum Information Transmission by Surface Acoustic Waves

National Metrology Institute of Japan

Key Components of Quantum Information Transmission
by Surface Acoustic Waves

TAKADA Shintaro
Research Institute for Physical Measurement

Succeeded in significantly improving electron transfer efficiency and enabling control of transfer timing

Electron transfer using surface acoustic waves (SAWs) is a promising method for transmitting quantum information. By using a coupled quantum rail and a single electron source triggered by a voltage pulse, we have succeeded in increasing the transfer efficiency from about 92 % to over 99 % and controlling the transfer timing which had been unclear.

SAW-driven single electron transfer technology is promising as fundamental technology for realization of quantum computers

To realize a quantum computer, quantum information must be transmitted between stationary nodes, and several methods have already been reported. One of them, the SAW-driven method, uses SAWs generated from a piezoelectric substrate to efficiently transport a single electron along a transport channel (quantum rail). SAW-driven quantum circuits for quantum computation have also been proposed. The challenges are to improve the transfer efficiency from the current level of about 92 % to more than 99 % and to establish a method to control the timing and direction of the transfer.

Highly efficient and precise control of single electrons demonstrates potential of SAW in quantum logic gates

We have developed two essential components for SAW-driven quantum circuits: a coupled quantum rail and a triggered single electron source. The coupled-quantum rail splits the flying electrons into two transport channels, while the triggered single electron source uses voltage pulses to perform SAW-driven transmission with picosecond-scale synchronization accuracy. Experimental results show that electrons are successfully transported along a pair of 20 µm-long quantum rails with a transfer efficiency as high as 99.75 %. Precise control of electron-transfer timing is also realized. In addition, it was also demonstrated that the transfer direction can be controlled by changing the gate voltage in the coupled-quantum rail.

This research is important milestone toward realization of quantum computing using SAW-driven electron transfer

The most part of the SAW burst used in this study is not involved in electron transport and can disturb the surrounding electrons before and after the electrons are transported. In addition, it is unclear at which position electrons are transported in the multiple SAW waves. To solve this problem, we have succeeded in generating an isolated pulse of intense SAWs using our originally developed comb-shaped electrode (AIST press release, September 7, 2022). In the future, by expanding the frequency bandwidth of the electrode, we aim to develop a technology for generating highly controllable SAW isolated pulses and to apply this technology to silicon-based materials, which are currently the mainstream in electron spin qubit research.

Contact for inquiries related to this theme

Quantum Electrical Standards Group, Research Institute for Physical Measurement

TAKADA Shintaro, Senior Researcher

AIST Tsukuba Central 3, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan

E-mail: info-ripm-ml*aist.go.jp (Please convert "*" to "@".)

Web: https://unit.aist.go.jp/ripm/en/

▲ ページトップへ