Observation of coherent single-electron dynamics is severely limited by experimental bandwidth. We present a method to overcome this using moving quantum dots defined by surface acoustic waves. Each dot holds a single electron, and travels through a static potential landscape. When the dot passes abruptly between regions of different confinement, the electron is excited into a superposition of states, and oscillates unitarily from side to side. We detect these oscillations by using a weak, repeated measurement of the current across a tunnel barrier, and find close agreement with simulations.
- surface acoustic waves
- quantum dots
Kataoka, M., Astley, M. R., Thorn, A. L., Oi, D. K. L., Barnes, C. H. W., Ford, C. J. B., Anderson, D., Jones, G. A. C., Farrer, I., Ritchie, D. A., & Pepper, M. (2009). Coherent time evolution of a single-electron wave function. Physical Review Letters, 102(15), [156801 ]. https://doi.org/10.1103/PhysRevLett.102.156801