Engineering Multi-electron Interactions for Quantum Logic in Silicon
Solid-state platforms are promising candidates for future quantum computers. Recent advances in solid-state nano-electronics have enabled precise control of individual atoms at atomic scales and manipulation of single qubits. Demonstration of high-fidelity two-qubit operations is being actively pursued and is currently the most sought after problem in the field of semiconductor quantum computing. A precise control of a two-qubit gate typically requires an in-depth understanding of the exchange of information between the electrons, which is complicated by the complex many-body quantum phenomena like correlation and entanglement. Accurate modeling of electron interactions is therefore of crucial importance in the effort towards scalable multi-qubit devices in the solid state. Atomistic Configuration Interaction (ACI), a portable, efficient and scalable computational tool for modeling electron-electron interactions in multi-electron quantum devices is implemented in the Nano-Electronic MOdeling (NEMO) software suite. The tool is validated against experimental data, in collaboration with the Centre for Quantum Computing and Communication Technology, CQCCT. Two-electron spectra and charge clouds are imaged at CQCCT and mapped to ACI simulation results to better understand electronic interactions on an atomic-scale in single donor atoms and coupled donor pairs. Furthermore, ACI is employed to investigate novel qubit architectures. Two-spin singlet-triplet and three-spin exchange-only qubits based on dopant atoms in silicon, enabling an all-electrical qubit control, are proposed and two-axis rotations towards electrically-controlled single qubit logic gates are demonstrated theoretically using ACI.
Rahman, Purdue University.
Electrical engineering|Quantum physics|Nanotechnology
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