Linear optics quantum computation

Quantum information has a dramatic impact on computational complexity, communication and cryptography. The discovery of quantum algorithms which have no efficient classical counterpart and of quantum error correction have lead to multiple proposals to implement these protocols in the laboratory. The first suggestion to manipulate quantum information has been using photonic technologies but its main drawback was the lack of strong interaction between photons. I will describe a proposal to use single photon sources, single photon detectors and linear optics (beam splitters and phase shifters) for quantum information. The fundamental idea is to use the non linearity of the measurement process to induce interaction between photons. Although this is not a unitary operation, I will describe how it is possible to simulate efficiently approximate unitary evolution using ideas from quantum teleportation and quantum error correction. I will finish by giving an overview of recent experimental steps towards implementing these ideas.