Coherent Control of Spin Qubits in High Density Quantum Dot Arrays in Silicon

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Computing power has increased exponentially in the last sixty years, all due to the continual improvement of the transistor, the building block of the computer. However, we are now starting to see diminishing returns on advancements in transistor technology. To overcome this, we must look to new sources of computational power, and quantum computers provide a promising solution to this. Quantum computers take advantage of quantum phenomena such as superposition and entanglement, this enables a speed-up for specific computational problems that even the best supercomputers would not be able to solve in a millennium. The quantum bit or qubit, the building block of a quantum computer, is used to encode information similar to how a bit is stored on a transistor. Various physical realisations of qubits, analogous to transistors, have been developed such as superconducting electronic circuits, atomic ions, particles of light and artificial atoms in silicon called quantum dots. With realisations of single qubits now becoming commonplace, research is shifting focus to building systems of multiple qubits. In this project we look to construct the first iteration of a three-by-three grid of qubits using silicon quantum dots. This presents a challenge due to the fragility of qubits, interactions between a qubit and its surrounding environment can lead to the loss of its quantum state. Therefore, adding multiple qubits together will present a challenge in mitigating their influence on one another, while maintaining individual control over each qubit such that they can carry out quantum computations. We will make use of the same processes that are used to make conventional silicon computer chips so that these qubits are compatible with existing industry for mass scale production.