Single-electron Spin Resonance in a Quadruple Quantum Dot

TL;DR

This paper demonstrates the control of individual electron spins in a quadruple quantum dot system using microwave-induced resonance, advancing scalable quantum computing architectures.

Contribution

It introduces a method for frequency-resolved addressable control of electron spins in a quadruple quantum dot with a micro-magnet, showing progress towards scalable quantum bits.

Findings

Successful demonstration of single-electron spin resonance in a quadruple quantum dot

Frequency-resolved control enabled by stray magnetic fields

Potential for scalable quantum information processing

Abstract

Electron spins in semiconductor quantum dots are good candidates of quantum bits for quantum information processing. Basic operations of the qubit have been realized in recent years: initialization, manipulation of single spins, two qubit entanglement operations, and readout. Now it becomes crucial to demonstrate scalability of this architecture by conducting spin operations on a scaled up system. Here, we demonstrate single-electron spin resonance in a quadruple quantum dot. A few-electron quadruple quantum dot is formed within a magnetic field gradient created by a micro-magnet. We oscillate the wave functions of the electrons in the quantum dots by applying microwave voltages and this induces electron spin resonance. The resonance energies of the four quantum dots are slightly different because of the stray field created by the micro-magnet and therefore frequency-resolved addressable control of the electron spin resonance is possible.