qopt: An experiment-oriented Qubit Simulation and Quantum Optimal Control Package

TL;DR

qopt is an open-source software framework for simulating realistic qubit dynamics and optimizing quantum control pulses, accounting for noise, hardware constraints, and experimental conditions to improve quantum processor performance.

Contribution

It introduces a comprehensive, experiment-oriented simulation and control optimization package that models noise, hardware limitations, and provides efficient gradient-based optimization for quantum control.

Findings

Enables simulation of realistic noise using multiple methods.

Supports modeling of hardware constraints like bandwidth and nonlinearities.

Facilitates efficient quantum control pulse optimization.

Abstract

Realistic modeling of qubit systems including noise and constraints imposed by control hardware is required for performance prediction and control optimization of quantum processors. We introduce qopt, a software framework for simulating qubit dynamics and robust quantum optimal control considering common experimental situations. To this end, we model open and closed qubit systems with a focus on the simulation of realistic noise characteristics and experimental constraints. Specifically, the influence of noise can be calculated using Monte Carlo methods, effective master equations or with the efficient filter function formalism, which enables the investigation and mitigation of auto-correlated noise. In addition, limitations of control electronics including finite bandwidth effects as well as nonlinear transfer functions and drive-dependent noise can be considered. The calculation of gradients based on analytic results is implemented to facilitate the efficient optimization of control pulses. The software easily interfaces with QuTip, is published under an open source license, well-tested and features a detailed documentation.