Abstract
The long-distance quantum transfer between electron-spin qubits in semiconductors is important for realising large-scale quantum computing circuits. Electron-spin to photon-polarisation conversion is a promising technology for achieving free-space or fibre-coupled quantum transfer. In this work, using only regular lithography techniques on a conventional 15 nm GaAs quantum well, we demonstrate acoustically-driven generation of single photons from single electrons, without the need for a self-assembled quantum dot. In this device, a single electron is carried in a potential minimum of a surface acoustic wave (SAW) and is transported to a region of holes to form an exciton. The exciton then decays and creates a single optical photon within 100 ps. This SAW-driven electroluminescence, without optimisation, yields photon antibunching with g(2)(0) = 0.39 ± 0.05 in the single-electron limit (g(2)(0) = 0.63 ± 0.03 in the raw histogram). Our work marks the first step towards electron-to-photon (spin-to-polarisation) qubit conversion for scaleable quantum computing architectures.
Highlights
The long-distance quantum transfer between electron-spin qubits in semiconductors is important for realising large-scale quantum computing circuits
A surface acoustic wave (SAW) is generated by applying a radio-frequency (RF) signal to an interdigitated transducer (IDT) at its resonant frequency fSAW = 1.163 GHz
Electrons are trapped in SAW potential minima and pushed towards the hole region (Fig. 1b)
Summary
The long-distance quantum transfer between electron-spin qubits in semiconductors is important for realising large-scale quantum computing circuits. While highfidelity qubit operations have been achieved in small-scale few-qubit systems[2,3,4], long-distance coupling between distant spin qubits in a large quantum circuit is a big challenge since the exchange interaction relies on the overlapping of two electron wavefunctions To solve this issue, many methods such as repeated SWAP operations[5], electron shuttling[6,7,8], and surface acoustic waves (SAWs)[9,10,11,12], have demonstrated quantum information transfer within a 10 μm length scale. To demonstrate the electron-to-photon conversion in the single-electron limit, the second-order correlation function, g(2) (0), where g(2)(0) ≤ 1 for sub-Poissonian light and g(2)(0) ≤ 0.5 for single-photon emission, needs to be measured when the SAW-
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