Talk: Individual electron and nuclear spin qubits controlled via superconducting circuits

Title: Individual electron and nuclear spin qubits controlled via superconducting circuits

Speaker: James O`Sullivan

Organizer: Chair of Experimental Physics (Prof. Eichler)

Abstract:

Electron Paramagnetic Resonance is a powerful spectroscopic technique for investigating paramagnetic materials, with applications in chemistry, biology, materials science, quantum computing and more. However, the field has largely been restricted to ensemble measurements involving large quantities of spins, owing to the weak coupling between electron spins and external magnetic fields. Measurement of individual spins has previously been restricted to selected systems, such as nitrogen-vacancy centres in diamond, with favourable properties which enable single-spin detection via optical readout or other means. I will present a platform for detection of generic single electron spins via inductive coupling to a superconducting resonator and a single microwave photon detector. I will show that a variety of techniques can be employed to manipulate both individual electron spins and nearby nuclear spins in solids, including single-shot quantum non-demolition measurement of individual 183W nuclear spins coupled to Er3+electron spin defects in a CaWO4 crystal host and entanglement of two 183W spins. We also study Tb3+ electron spins in CaWO4 at magnetic field noise insensitive points known as 'clock transitions'. Operation at these points yields electron spin coherence times in excess of 10 ms, enabling coherent interaction between individual Tb3+ spins and the electromagnetic field of the superconducting resonator.