Demonstration of the Deutsch-Jozsa algorithm with single photons

Full text: Among the numerous other concepts of implementing qubits for quantum computation, single photons have been a particularly useful working horse for studying entanglement, quantum information and quantum computation. The Deutsch-Jozsa algorithm as one of the first quantum algorithms illustrating the vast potential of quantum computation has been already realized in NMR or ion-trap quantum computing. The task of the Deutsch-Jozsa algorithm is to determine if a function f is constant or balanced. It requires only 1 evaluation of f, whereas a classical computer would need 2n-1 +1 evaluations for a n bit function. For the case of a 2 bit function the algorithm can be demonstrated using single photons and linear optics. In our experiment the first qubit is implemented by two spatial modes of the photon and the second qubit by the polarization of the photon. Single photons are provided by a source using InP quantum dots. Further experimental demonstrations of fundamental quantum effects are discussed. (author)