Microscopic Noise Model for Two-qubit Gates in Silicon Quantum Dot Arrays

Abstract

This thesis presents and validates a numerical model to capture and reproduce the effects of nuclear and charge noise in affecting spin qubits in semiconductor quantum dots. Charge noise with a 1/f spectral density is nearly ubiquitous in solid state systems, especially when scale is small enough that environmental interactions are quantum mechanical. While nuclear noise has largely been mitigated by choosing materials that are naturally mostly spinless and by further purifying them of spinful isotopes, and the effects of charge noise can be avoided by particular methods, quantum operations in quantum dot systems are limited by electric fluctuations in the surrounding heterostructure. Recent studies report single and two qubit fidelities exceeding 99% [10,17,18] but the development of this quantum computing platform beyond two qubits will continue to face the challenges of charge noise. The purpose of this thesis is to give a broad overview of quantum dot systems and the physical princples that model them in order to serve as an introduction to the field, and to confirm microscopic understandings of noise.