Quantum computation – principles and solid-state concepts

In this chapter we review the basics of quantum computation and discuss promising physical systems for implementation of a qubit. The advantage of quantum computation over classical computation is shown by presenting the quantum algorithms for searching databases and factorizing numbers. In addition, quantum bits are ideal candidates for secure communication. The operation scheme and error correction of quantum computation are reviewed. First experimental realization of quantum computation by nuclear magnetic resonance is outlined. Several types of scalable solid-state qubits based on semiconductors and superconducting Josephson junctions (charge, flux and fractional flux qubits) are presented