Nuclear Quantum Information Processing Controlled via Hyperfine Interaction with Electrons

Objective

Quantum RAM (QRAM) is a key quantum computing resource featuring in many theoretical proposals that has never been demonstrated in experiment. A QRAM is a quantum memory in which one can read or write quantum information to a superposition of memory cells. Such a device is powerful as a tool for implementing many quantum algorithms, including Grover’s search algorithm, quantum chemistry, quantum cryptography and quantum machine learning, and is regarded by many as essential for a future quantum computer. Nuclear Quantum Information processing Controlled via Hyperfine interaction with Electrons (nQUICHE) aims to use recently developed techniques in single spin detection, spectroscopy and coherent control to demonstrate a quantum router, the unit cell of a QRAM, using electron and nuclear spins in the solid state coupled to superconducting circuits. The hybrid spin architecture proposed in nQUICHE has a baked-in double controlled-SWAP interaction that efficiently routes quantum information into memory qubits with seconds-long coherence times, making the system particularly well suited to realising a QRAM. Beyond QRAM, nQUICHE will expand the toolbox of techniques for solid state spin quantum information processing and will investigate new crystal hosts and an alterative spin system with a large nuclear spin of 7/2, exploring its 16-dimensional Hilbert space. Architectures for controlling large arrays of spins and interfacing with superconducting circuits in a scalable, modular architecture will be developed. These experiments are relevant not only for constructing a QRAM, but also for quantum computation and networking with this platform. The techniques developed will push the frontiers of electron paramagnetic resonance. In addition to having technological applications, experiments performed during nQUICHE will explore novel effects with single spins that are of interest from a purely fundamental physics perspective.