Quantum Computation and Information Seminar 

06/06/2014, 16:15 — 17:15 — Room P3.10, Mathematics Building
Hamed Mohammady, Physics of Information Group - IT

Nuclear-electronic spin systems, magnetic resonance, and quantum information processing

A promising platform for quantum information processing is that of silicon impurities, where the quantum states are manipulated by magnetic resonance. Such systems, in abstraction, can be considered as a nucleus of arbitrary spin coupled to an electron of spin one-half via an isotropic hype rfine interaction. We therefore refer to them as "nuclear-electronic spin systems". The traditional example, being subject to intensive experimental studies, is that of phosphorus doped silicon (Si:P) which couples a spin one-half electron to a nucleus of the same spin, with a hyperfine strength of 117.5 MHz. More recently, bismuth doped silicon (Si:Bi) has been suggested as an alternative instantiation of nuclear-electronic spin systems, differing from Si:P by its larger nuclear spin and hyperfine strength of 9/2 and 1.4754 GHz respectively. Here we develop a model that is capable of predicting the magnetic resonance properties of nuclear-electronic spin systems, which has proven to be in good agreement with experiments. Furthermore, we show that the larger nuclear spin and hyperfine strength of Si:Bi, compared with that of Si:P, offer advantages for quantum information processing by providing magnetic field-dependent two-dimensional decoherence free subspaces, called optimal working points or clock transitions, which have been identified to exist in Si:Bi, but not Si:P.