Electron spins confined to semiconductor quantum dots can act as qubits, with the exchange interaction between them driving two-qubit gates. Taking advantage of the existing CMOS integration technologies, such devices can offer a platform for large scale quantum computation. However, a quantum mechanical framework bridging the devices’ physical design and operational parameters to the qubit’s energy space is lacking. Furthermore, the coherence of spin qubits is limited by charge noise that is ubiquitous in electronic devices. In this work, we present a co-modelling framework for electron spins in realistic quantum dot devices together with their charge noise environment.
We develop a versatile configuration-interaction based quantum mechanical model to estimate the energy spectra and exchange interaction of spins in quantum dot systems. The model takes electrostatic potentials of realistic devices as an input rather than fictitious parabolic potentials. In addition, the model is flexible to include any external potentials that can be used to represent the charge noise. We further develop a microscopic model of charge noise based on the distributions of Two-Level-Fluctuators (TLFs), representing the device’s realistic electrostatic operation conditions. The fluctuations of charge noise are finally fed into the qubit-model to estimate the shifts in exchange interactions and quantum gate fidelities. The co-modelling framework developed here gives insights into the devices’ operational conditions, thus enabling the study of optimization paths.