High-Dimensional Quantum Information Processing in Silicon

Fault-tolerant computation usually builds an error-correctable logical qubit by entangling several physical qubits. Even when it represents one quantum bit, this logical object occupies a higher-dimensional space. Andrea Morello discusses a different approach that stores quantum information directly in a naturally high-dimensional physical system.

The system uses an antimony nucleus with spin I = 7/2 and an eight-dimensional Hilbert space. As a group-V donor, the atom can be implanted into a silicon nanoelectronic device. Its nuclear spin supports Schrödinger-cat states that serve as logical codewords, without constructing them from multiple entangled physical qubits. Encoding employs a generalized rotating frame made possible by modern FPGA signal generators, including the Quantum Machines OPX. The talk considers this control infrastructure as a route to quantum-computing hardware that uses fewer resources.