Condensed Matter and Biological Physics Seminars

Numerous challenges arise in the fabrication of quantum bits in the solid state. Spins in silicon form a promising candidate for quantum computation, due to desirable coherence properties. However, the silicon band structure poses a special challenge, in terms of valley degeneracy. I will review the proposal for quantum dot quantum computing in silicon, and develop a theory of valley splitting, which predicts that the greatest threat to silicon qubits may arise from a surprising source: rough interfaces in the quantum well. Fortunately, lateral confinement in the quantum dot geometry ameliorates this situation. I discuss some recent experiments in support of our theory.