  Quantum computing is an attractive and multidisciplinary field, which became
a focus for experimental and theoretical research during last decade. Among
other systems, like ions in traps or superconducting circuits, solid-states
based qubits are considered to be promising candidates for first experimental
tests of quantum hardware. Here we report recent progress in quantum
information processing with point defect in diamond. Qubits are defined as
single spin states (electron or nuclear). This allows exploring long coherence
time (up to seconds for nuclear spins at cryogenic temperatures). In addition,
the optical transition between ground and excited electronic states allows
coupling of spin degrees of freedom to the state of the electromagnetic field.
Such coupling gives access to the spin state readout via spin-selective
scattering of photon. This also allows using of spin state as robust memory for
flying qubits (photons).
