qopt: A Python Software Package for Quantum Simulation and Optimal Control

We introduce qopt, a software framework for robust quantum optimal control considering realistic experimental conditions. To this end, we model open and closed qubit systems with a focus on the simulation of noise sources and experimental constraints. Specifically, the influence of noise can be calculated using Monte Carlo methods, effective master equations or with the filter function formalism, enabling the investigation and mitigation of auto-correlated noise. In addition, limitations of control electronics including finite bandwidth effects can be considered. The calculation of gradients based on analytic results is implemented to facilitate the efficient optimization of control pulses. The software is published under an open source license, well tested and features a detailed documentation [1].
We demonstrate the simulation capability of the package by analysing leakage of the flopping-mode spin qubit, which is realized by delocalizing a single electron over a double quantum dot. This leads to larger electric dipole moments and thus facilitates fast electron dipole spin resonance [2].
[1] https://git-ce.rwth-aachen.de/qutech/qopt
[2] Benito et al., Phys. Rev. B 100, 125430 (2019)