Double Occupancy Errors in Quantum Computing Operations: Corrections to Adiabaticity

TL;DR

This paper analyzes errors caused by double occupancy in quantum dot spin-qubits during adiabatic quantum operations, providing a model that accurately predicts transition probabilities and clarifies conditions for adiabaticity.

Contribution

It introduces an integrable two-level model for double occupancy errors, confirms the accuracy of Dykhne's formula, and aligns semiclassical predictions with numerical simulations.

Findings

Dykhne's formula accurately estimates non-adiabatic transition probabilities.

Semiclassical results match numerical simulations closely.

Physically intuitive conditions for adiabaticity validity are discussed.

Abstract

We study the corrections to adiabatic dynamics of two coupled quantum dot spin-qubits, each dot singly occupied with an electron, in the context of a quantum computing operation. Tunneling causes double occupancy at the conclusion of an operation and constitutes a processing error. We model the gate operation with an effective two-level system, where non-adiabatic transitions correspond to double occupancy. The model is integrable and possesses three independent parameters. We confirm the accuracy of Dykhne's formula, a nonperturbative estimate of transitions, and discuss physically intuitive conditions for its validity. Our semiclassical results are in excellent agreement with numerical simulations of the exact time evolution. A similar approach applies to two-level systems in different contexts.