Spin Qubits in Multi-Electron Quantum Dots

TL;DR

This paper investigates how mesoscopic fluctuations affect error rates in exchange operations of spin qubits in multi-electron quantum dots, emphasizing the importance of precise control of electrode voltages for reliable quantum computing.

Contribution

It provides a detailed analysis of error sources in mid-size double quantum dots with multi-electron occupancy using realistic models, highlighting the parameter tuning needed for accurate control.

Findings

Short pulses require precise voltage control within a few percent.

Number of parameters to tune varies from one to four depending on the configuration.

Mesoscopic fluctuations significantly impact error magnitudes in quantum dot spin-qubits.

Abstract

We study the effect of mesoscopic fluctuations on the magnitude of errors that can occur in exchange operations on quantum dot spin-qubits. Mid-size double quantum dots, with an odd number of electrons in the range of a few tens in each dot, are investigated through the constant interaction model using realistic parameters. It is found that the constraint of having short pulses and small errors implies keeping accurate control, at the few percent level, of several electrode voltages. In practice, the number of independent parameters per dot that one should tune depends on the configuration and ranges from one to four.