In the last few years quantum information has played an increasingly central role in the research activities of many scientists within wide ranging areas of physics, mathematics and computer science as it known to be more efficient than its classical counterpart. The impact and advantages of quantum information protocols emerge in numerous situations. In the case of cryptography, quantum dynamics guarantees secure protocols, and in quantum computation, factorization of large numbers, intractable with classical algorithms, can be solved much faster with a quantum computer. It is now widely believed that quantum information will play a leading role in future technologies.

Together with the ongoing development of more efficient schemes to solve both new and old tasks in information science, a great deal of interest has been devoted to selecting suitable physical systems where one could realize these ideas. In particular, the quest for large scale integrability has stimulated an increasing interest in the field of solid state physics. Nanoelectronics seems the natural arena to realize physical implementation of quantum hardware. Qubits made out of solid-state devices, such as spins/charges in quantum dots or superconducting nanocircuits, may offer a greater advantage in this respect because fabrication techniques allow for scalability to a large number of coupled qubits. Recent experimental breakthroughs in semiconducting and superconducting nanostructures constitute the first important steps towards the realization of a solid-state quantum computer. In addition the interest in solid state quantum computation has stimulated a large body of research aimed at understanding the properties of entanglement in solid state systems.

This Focus issue of New Journal of Physics gathers together contributions from leading experts in the area of solid state quantum information with the aim of providing a panorama of the most exciting scientific questions currently being investigated in the field.

Focus on Solid State Quantum Information Contents

Quasiparticle entanglement: redfinition of the vacuum and reduced density matrix approach
P Samuelsson, E Sukhorukov and M Buttiker

Pseudospin quantum computation in semiconductor nanostructures
V W Scarola, K Park and S Das Sarma

Superconducting qubit network with controllable nearest-neighbour coupling
M Wallquist, J Lantz, V S Shumeiko and G Wendin

Weak coupling Josephson junction as a current probe: effect of dissipation on escape dynamics
J M Kivioja, T E Nieminen, J Claudon, O Buisson, F Hekking and J P Pekola

The single Cooper-pair box as a charge qubit
K Bladh, T Duty, D Gunnarsson and P Delsing

Quantum state transfer in arrays of flux qubits
A O Lyakhov and C Bruder

Spin filling of a quantum dot derived from excited-state spectroscopy
L H Willems van Beveren, R Hanson, I T Vink, F H L Koppens, L P Kouwenhoven and L M K Vandersypen

Clauser–Horne inequality for the full counting statistics
F Taddei, R Fazio and E Prada

Recent advances in exciton based quantum information processing in quantum dot nanostructures
H J Krenner, S Stufler, M Sabathil, E C Clark, P Ester, M Bichler, G Abstreiter and J J Finley

Spatially highly resolved study of AFM scanning tip-quantum dot local interaction
S Kicin, A Pioda, T Ihn, M Sigrist, A Fuhrer, K Ensslin, M Reinwald and W Wegscheider

Transfer of entanglement from electrons to photons by optical selection rules
M Titov, B Trauzette, B Michealis and C W J Beenakker

Non-Abelian Chern-Simons models with discrete gauge groups on a lattice
B Doucot and L B Ioffe

Landau–Zener transitions in qubits controlled by electromagnetic fields
Martijn Wubs, Keiji Saito, Sigmund Kohler, Yosuke Kayanuma and Peter Hänggi

Phase-slip flux qubits
J E Mooij and C J P M Harmans

Mediated tunable coupling of flux qubits
Alec Maassen van den Brink, A J Berkley and M Yalowsky

Divergent beams of nonlocally entangled electrons emitted from hybrid normal-superconducting structures
Elsa Prada and Fernando Sols

Decoherence from ensembles of two-level fluctuators
Josef Schriefl, Yuriy Makhlin, Alexander Shnirman and Gerd Schön

Semiconductor quantum dots for electron spin qubits
W G van der Wiel, M Stopa, T Kodera, T Hatano and S Tarucha

Rosario Fazio, NEST-INFM and Scuola Normale Superiore, Pisa, Italy