A proposal for the implementation of quantum gates with photonic-crystal waveguides

Quantum computers require technologies that offer both sufficient control over coherent quantum phenomena and minimal spurious interactions with the environment. We argue that, photons confined to photonic crystals, and in particular to highly efficient waveguides formed by linear chains of defects, doped with atoms or quantum dots, can generate strong nonlinear interactions between photons allowing for the implementation of both single and two-qubit quantum gates. The simplicity of the gate switching mechanism, the experimental feasibility of fabricating two-dimensional photonic-crystal devices and the integrability of such devices with optoelectronic components offer new interesting possibilities for optical quantum-information processing networks.