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A state-of-the-art quantum transport simulator.
A first-class quantum transport simulator.
A powerful material physics simulator.
Our most powerful solution for first-principles materials simulation.
Allows finite element modeling for computer-aided design of quantum-technology hardware.
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A computer-aided design tool for quantum-technology hardware.
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New release

QTCAD® is available for academic, government institution and private company users for download!
Please contact us to know more about this unique software.

QTCAD® is a computer-aided design tool for
quantum semiconductor-based hardware.

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Who are the customers
using QTCAD®?

Experimental physicists and quantum engineers

Gain a microscopic understanding of latest experiments using finite-element simulations and predict the performance of next-generation quantum devices.

Theoretical physicists

Validate analytic models against realistic finite-element simulations accounting for full device geometry and perform numerical experiments to test your latest ideas in quantum device design, quantum-computing architecture, quantum control, and more.



Specifically designed for spin qubits

QTCAD® calculates quantities related to spin-qubit systems, such as eigenenergies and envelope functions for confined electrons and holes, many-body energies and chemical potentials, charge stability diagrams, Rabi oscillations, and more.

Arbitrary 2D and 3D geometry

Produce a CAD model for any device of interest and its corresponding first or second-order Lagrange finite-element mesh using Gmsh, and import it into QTCAD® to define and run simulations.

Using QTCAD® is convenient and easy

Use our Python-based device editing UI to import layouts directly from your GDS file, and specify your heterostructure stack along the growth direction. Our flexible Python API allows users to define and launch a simulation in a few lines of code, and seamlessly integrate with third-party software for data visualisation and analysis, or even with other Python-based software from the quantum ecosystem (e.g. QuTiP) .

Adaptive meshing

QTCAD®'s adaptive meshing procedure enables it to predict the electrostatic properties of spin qubits at cryogenic temperatures (below 1 K), something that other commercially available TCAD software cannot do.

Try QTCAD® for free

Download the QTCAD® leaflet to get a summary of the software features!

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QTCAD® (Quantum-Technology Computer-Aided-Design) is a finite-element (FEM) simulator used to predict the performance of spin-qubit devices before their production. QTCAD® simulations can lead to huge savings in both time and money since they allow users to explore many design scenarios before their implementation in the lab.

Flexible, scriptable, and user-friendly interface

Gated geometries can be imported directly from standard layout (.gds) files used to design integrated circuits [layout.png]. Heterostructure stacks are defined through our simple Python API. This approach captures the geometry of most gated quantum dots. For expert users, arbitrary 2D and 3D geometries and their corresponding mesh can be defined and customized at will using Gmsh.

Electrostatics at cryogenic temperature

QTCAD®’s non-linear Poisson solver can predict the confinement potential of quantum dots in semiconductor nanostructures under split gates. QTCAD is designed to converge at sub-Kelvin temperatures in many practical spin-qubit designs. Low-temperature convergence is notoriously difficult with other currently available TCAD software.

Schrodinger solvers

QTCAD®’s Schrödinger solver calculates the wave functions of electrons or holes in realistic confinement potentials. These confinement potentials are determined by applying QTCAD’s non-linear Poisson solver to specific device geometries. Thus the computed wavefuntions can be used to predict if a given candidate device can host bound states.

Many-body physics

QTCAD® can assemble and exactly diagonalize the many-body Hamiltonian for few-electron or few-hole systems under quantum confinement using a truncated basis built from real-space single-body eigenfunctions of the device. This approach yields accurate chemical potentials and addition-energy spectra for realistic quantum dots accounting for the Coulomb interaction between confined electrons or holes.

Transport physics

Our master equation solver leverages QTCAD®’s many-body physics capabilities to calculate the current flowing through quantum-dot systems in the sequential tunneling regime. This enables the treatment of Coulomb blockade and the prediction of charge stability diagrams used to demonstrate the few-electron or few-hole regime in experiments.

Valley-splitting physics

For silicon-based devices, lifting the valley degeneracy is a vital step to isolate well-defined qubit eigenstates. QTCAD® includes a module that calculates valley splitting due to sharp heterostructure interfaces using matrix elements in the basis of Bloch states calculated with our atomistic simulation software RESCU.

Gate fidelity for realistic device geometries

Ultimately, QTCAD® determines the system Hamiltonian, accounting for realistic device geometry. Once the system Hamiltonian is known, qubit time-evolution can be evaluated using third-party time-dependent Schrödinger solvers (e.g., QuTiP). In this figure, we show Rabi oscillations for a spin-qubit device under electric-dipole spin resonance. We account for a realistic inhomogeneous magnetic field, and for the precise geometry of electric fields acting on the quantum dot due to applied and charge-noise-induced gate potentials.

Multiscale platform

Interface with our large scale DFT software RESCU to calculate material parameters that enter the k.p theory.

Cross-platform implementation

QTCAD® can easily be deployed on Linux, MacOS, and Windows machines, on personal computers and clusters alike.

What's new ?

QTCAD® is now commercially available for academic users: we invite you to download the free trial version and test it. We maintain in parallel our beta testing program with our advanced users worldwide to  contribute to the future versions of QTCAD®. Thank you very much in advance, see you soon!


Current version of QTCAD is 1.4.0.

QTCAD user documentation

To access to QTCAD® user documentation, click the link below: installation and user manuals, tutorials, theory and technical information pages are all there for your support and to get you up to speed as quickly as possible.

Developed in close collaboration with:

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