Quantum computation with moving quantum dots generated by surface acoustic waves

TL;DR

This paper proposes a theoretical method for quantum computation using electrons trapped in moving quantum dots generated by surface acoustic waves, enabling single and two-qubit operations with current detection techniques.

Contribution

It introduces a novel approach to quantum computing with moving quantum dots driven by surface acoustic waves, including qubit encoding and two-qubit gate implementation.

Findings

Single-electron qubits can be encoded in moving quantum dots.

Rabi oscillations can be achieved with microwave pulses.

Two-qubit i-SWAP gate can be realized via Coulomb interaction.

Abstract

Motivated by the recent experimental observations [M. Kataoka et al., Phys. Rev. Lett. {\bf102}, 156801 (2009)], we propose here an theoretical approach to implement quantum computation with bound states of electrons in moving quantum dots generated by the driving of surface acoustic waves. Differing from static quantum dots defined by a series of static electrodes above the two-dimensional electron gas (2DEG), here a single electron is captured from a 2DEG-reservoir by a surface acoustic wave (SAW) and then trapped in a moving quantum dot (MQD) transporting across a quasi-one dimensional channel (Q1DC), wherein all the electrons have been excluded out by the actions of the surface gates. The flying qubit introduced here is encoded by the two lowest adiabatic levels of the electron in the MQD, and the Rabi oscillation between these two levels could be implemented by applying finely-selected microwave pulses to the surface gates. By using the Coulomb interaction between the electrons in different moving quantum dots, we show that a desirable two-qubit operation, i.e., i-SWAP gate, could be realized. Readouts of the present flying qubits are also feasible with the current single-electron detected technique.