Introduction

QTCAD is a simulation platform for quantum technology developed by Nanoacademic Technologies Inc. QTCAD includes finite-element and atomistic modeling capabilities, thereby enabling multiscale simulations. The main features of QTCAD are:

• An electrostatics tool that solves the confining potential of quantum dots in semiconductor nanostructures and finds corresponding envelope functions for electrons or holes.

• A capacitance matrix solver that can be used to extract self and coupling capacitances between components of superconducting circuits.

• A frequency-domain finite-element Maxwell solver that may be used to compute the eigenmodes of superconducting resonators and cavities.

• Valley-splitting calculation tools at the finite-element and atomistic levels.

• \(g\)-tensor calculation tools at the finite-element and atomistic levels.

• An exact diagonalization tool for the treatment of Coulomb interactions in few-electron systems.

• A master equation solver for quantum transport calculations in the sequential tunneling regime enabling the treatment of Coulomb blockade and the calculation of charge-stability diagrams.

• A solver based on the nonequilibrium Green’s function formalism to resolve nonequilibrium quantum statistics and transport properties of nanoelectronic devices.

• An electric-dipole spin resonance module that interfaces with QuTiP for time-dependent simulations of quantum control.

• A painless treatment at cryogenic (sub-K) temperatures of several designs of solid-state spin qubits.

• A user-friendly Python application programming interface (API) to launch simulations.

• An atomic structure builder to model the atomic structure of quantum dots, including realistic nonidealities such as random alloying and rough heterointerfaces, and atomistic strain effects.

• Compatibility with devicegen, an open-source Python API enabling to define gated quantum dot geometries from gate layouts (GDS files).

On this QTCAD documentation website, you will learn how to run a simulation in QTCAD from installation to advanced features. This website is divided into the following pages:

• Installation provides instructions on how to install QTCAD and its dependencies.

• License Activation provides instructions on how to obtain your license.

• Getting Started walks you through a very simple calculation example for QTCAD.

• Theory – Finite Elements (Semiconductors) explains the fundamental theoretical models that underpin QTCAD for semiconductor quantum devices.

• Theory – Atomistics (Semiconductors) explains the fundamendal theoretical atomistic models in QTCAD.

• Theory (Superconductors) explains the theoretical models behind the superconducting quantum device analysis in QTCAD.

• Tutorials (Semiconductors) and Tutorials (Superconductors) contain how-to’s and tutorials for all calculation types and more.

• Practical Application demonstrates the capabilities of QTCAD for semiconductor quantum device analysis in a practical context. Namely, it explains the modeling and simulation of a gated quantum dot.

• API Reference provides detailed documentation for QTCAD modules and classes.

• Troubleshooting provides troubleshooting for frequent issues (e.g., issues related to installation).

• Contact Us tells you how to reach us regarding any QTCAD-related comment/question you might have.

• Citing QTCAD provides information on how to cite QTCAD in your publications.

• Bibliography provides a list of references used in the documentation.