Quantum computing with spins in solids

TL;DR

This paper reviews the Loss-DiVincenzo proposal for quantum computing using electron spins in quantum dots, emphasizing the scalability and current experimental and theoretical progress in single and double quantum dot systems.

Contribution

It provides a systematic review of the Loss-DiVincenzo quantum dot spin qubit proposal and surveys recent experimental and theoretical developments.

Findings

Strong Heisenberg exchange coupling enables scalable qubit interactions.

Experimental progress in single and double quantum dots supports the proposal.

Analysis of alternative quantum computing schemes is included.

Abstract

The ability to perform high-precision one- and two-qubit operations is sufficient for universal quantum computation. For the Loss-DiVincenzo proposal to use single electron spins confned to quantum dots as qubits, it is therefore sufficient to analyze only single- and coupled double-dot structures, since the strong Heisenberg exchange coupling between spins in this proposal falls off exponentially with distance and long-ranged dipolar coupling mechanisms can be made significantly weaker. This scalability of the Loss-DiVincenzo design is both a practical necessity for eventual applications of multi-qubit quantum computing and a great conceptual advantage, making analysis of the relevant components relatively transparent and systematic. We review the Loss-DiVincenzo proposal for quantum-dot-confned electron spin qubits, and survey the current state of experiment and theory regarding the relevant single- and double- quantum dots, with a brief look at some related alternative schemes for quantum computing.