Optomechanical quantum bus for spins in silicon

ended

Silicon has been the material underpinning the modern information technology revolution. I would argue that it might be the most important material of the coming quantum technology age as well. This will be of tremendous advantage to the diffusion of quantum technologies as they can then leverage the existing infrastructure of silicon electronics and photonics. My project is aimed at unlocking the quantum potential of silicon technologies. It is aimed at enabling a not too distant future where silicon chips encompassing quantum enabled sensors and/or quantum computing processors are widely available and only require push-of-a-button coolers and laser light to operate. Qubits are of fundamental interest not only for the tantalizing prospect of building a quantum computer but also because they can work as powerful quantum sensors. In this project, I will advance a novel emerging physical implementation of qubits: donor spin states in silicon. These states are now known to be excellent qubits with the longest single qubit coherence times demonstrated in solid state. This is a significant advantage for both quantum sensing and quantum information applications. However, at the moment the application potential of silicon donor qubits is hindered by two related obstacles: current readout techniques require nanoelectric connections, millikelvin temperatures and high magnetic fields, and - most importantly - there are no scalable methods to couple multiple qubits. This project will realize an optomechanical quantum bus for spins in silicon in order to enable optical and mechanical coupling and readout mechanisms for the donor spins and hence overcome all these obstacles. The created quantum bus will not only allow integrating the spin qubits with existing silicon photonics and NEMS platforms for integrated quantum circuits and optically readable practical quantum sensors but will also provide a solid-state on-chip testbed for creating and studying macroscopic quantum states.