Multi-level spectral navigation with geometric diabatic-adiabatic control

TL;DR

This paper presents a geometric framework for optimizing quantum control pulses in multi-level systems, enabling high-fidelity state transfer beyond adiabatic limits by interpolating between diabatic and adiabatic dynamics.

Contribution

It introduces a novel geometric approach that simplifies multi-parameter pulse optimization to solving a first-order ODE, enhancing control efficiency in quantum systems.

Findings

Effective high-fidelity state transfer demonstrated in spin-based quantum information tasks.

Method reduces complex optimization to a simple differential equation.

Flexible protocols applicable to various quantum control scenarios.

Abstract

We introduce a geometric framework for efficient few-parameter pulse optimization in multi-level quantum systems, enabling high-fidelity state transfer beyond the adiabatic limit. Our method interpolates smoothly between adiabatic and diabatic dynamics to minimize unwanted excitations and maximize desired transitions even within a multi-level structure. Crucially, for single-parameter pulse control, the optimization reduces to solving a first-order ordinary differential equation. We showcase the flexibility of our diabatic-adiabatic protocols through two examples in spin-based quantum information processing: state initialization and qubit state transfer.