## Scalable quantum computing based on stationary spin qubits in coupled quantum dots    [PDF]

Hai-Rui Wei, Fu-Guo Deng
Quantum logic gates are fundamental building blocks in quantum information processing. Here we investigate the possibility to achieve scalable quantum information processing based on stationary electron-spin qubits, by using the giant optical circular birefringence induced by quantum-dot spins in double-sided optical microcavities as a result of cavity quantum electrodynamics. We design the quantum circuits for implementing universal and deterministic quantum gates for electron-spin systems, including two-qubit controlled-not, $\sqrt{\textrm{SWAP}}$, SWAP, three-qubit Toffoli and Fredkin gates. They have good scalability and are attractive as they are compact and all are based on solid-state quantum systems. Moreover, our devices do not require additional electron-spin qubits and they are feasible with current experimental technology. Both high fidelity and high efficiency can be achieved when the side leakage to the cavity decay is low.
View original: http://arxiv.org/abs/1307.0251