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Silicon quantum dots
Spin qubits are one of the prospective qubits for future scalable quantum computers . However, reliable fabrication of these basic quantum elements is challenging and requires nearly perfect materials and nanometer precision owing to their small size and sensitivity to the electromagnetic environment. Silicon, which has been the material of choice for classical computing for many years, also has highly desirable properties for the fabrication of spin qubits [2-8].
Individually confined electron and hole spins in silicon-based quantum dots have been shown to have exceptionally long lifetimes, up to seconds or longer for electrons in isotopically purified 28Si [3,4,6].
Owing to the tremendous advancement of silicon technology in recent years, reliable fabrication of silicon quantum dots has come within reach. Some of the silicon transistor devices in the latest technology nodes can actually be used directly as spin qubits .
“Our goal is to engineer the quantum coupling between silicon qubits and microwave photon states. ”
—IBM scientist Andreas Fuhrer
However, one of the problems that currently plagues all spin-qubit architectures is the unresolved question of long-range coupling. Such coupling is needed for the operation of a 2D qubit-lattice as required by topological surface codes that provide quantum error correction. In this context, we are investigating silicon quantum dots and their coupling to superconducting microwave resonators .
We aim to address the coupling issue and draw a link to the more advanced superconducting qubit platform that IBM is working on . We are also investigating the coupling of spins to surface-acoustic waves as an alternative to microwave resonators.