Quantum Computing with Solid-State Systems

Abstract

This chapter highlights some general concepts that have relevance for most solid‐state quantum computing proposals. The exchange coupling between electron spins is an important paradigm for most solid‐state quantum computing proposals, even those where the qubit is not a real spin, but a pseudospin, which can be any other type of quantum two‐level system. Even the pseudospin in superconducting (SC) qubits is coupled via an anisotropic exchange coupling. In semiconductor optical cavities, the coupling between spins in quantum dots (QDs) can be achieved without tunnel coupling between the dots, but instead via emission and reabsorption of virtual cavity photons. The chapter then discusses the physics of two types of solid‐state qubit systems: electron spin‐based qubits in semiconductors and SC circuits with Josephson junctions. One of the eminent features of many solid‐state systems studied for quantum information processing is their scalability.