Proceedings of the NATO Advanced Research Workshop, held in Granada, Spain, 6-12 September 2003

Decoherence and Dephasing.- Electron Dephasing in Mesoscopic Metal Wires.- Decoherence Effects in the Josephson Current of a Cooper Pair Shuttle.- Dephasing in Disordered Metals with Superconductive Grains.- Decoherence in Disordered Conductors at Low Temperatures: The Effect of Soft Local Excitations.- Quantum Precursor of Shuttle Instability.- Dephasing and Dynamic Localization in Quantum Dots.- Mesoscopic Aharonov-Bohm Oscillations in Metallic Rings.- Influence Functional for Decoherence of Interacting Electrons in Disordered Conductors.- Entanglement and Qubits.- Low-Frequency Noise as a Source of Dephasing of a Qubit.- Entanglement Production in a Chaotic Quantum Dot.- Creation and Detection of Mobile and Non-Local Spin-Entangled Electrons.- Berezinskii-Kosterlitz-Thouless Transition in Josephson Junction Arrays.- Interactions in Normal and Superconducting Systems.- Quantum Coherent Transport and Superconductivity in Carbon Nanotubes.- Quantum Hall Ferromagnets, Co-Operative Transport Anisotropy, and the Random Field Ising Model.- Exotic Proximity Effects in Superconductor/Ferromagnet Structure.- Transport in Luttinger Liquids.- Interaction Effects on Counting Statistics and the Transmission Distribution.- Variable-Range Hopping in One-Dimensional Systems.- On the Electron-Electron Interactions in Two Dimensions.- Correlations and Spin in Transport Through Quantum Dots.- Interactions in High-Mobility 2D Electron and Hole Systems.

Mesoscopic physics deals with effects at submicron and nanoscales where the conventional wisdom of macroscopic averaging is no longer applicable. A wide variety of new devices have recently evolved, all extremely promising for major novel directions in technology, including carbon nanotubes, ballistic quantum dots, hybrid mesoscopic junctions made of different type of normal, superconducting and ferromagnetic materials. This, in turn, demands a profound understanding of fundamental physical phenomena on mesoscopic scales. As a result, the forefront of fundamental research in condensed matter has been moved to the areas where the interplay between electron-electron interactions and quantum interference of phase-coherent electrons scattered by impurities and/or boundaries is the key to such understanding. An understanding of decoherence as well as other effects of the interactions is crucial for developing future electronic, photonic and spintronic devices, including the element base for quantum computation.