QCD and strongly coupled gauge theories : challenges and perspectives

We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe

Optimization of RF- and DC-sputtered NbTiN films for integration with Nb-based SIS junctions

NbTiN is one of the most promising materials for use in the tuning circuits of Nb-based SIS mixers for operating frequencies above the gap frequency of Nb (/spl ap/700 GHz). We examine the properties of NbTiN films obtained using an unbalanced sputtering source in both RF and DC operating regimes. It is found that the properties of NbTiN films are strongly affected by the total pressure of the sputtering process. Films obtained under lower pressures have higher compressive stresses and lower resistivities. The best NbTiN films are obtained by DC sputtering and have a transition temperature of 14.4 K, a resistivity of 90 /spl mu//spl Omega//spl middot/cm at 20 K, and a compressive stress of -1 GPa. Films with a resistivity of 110 /spl mu//spl Omega//spl middot/cm at 20 K and a compressive stress of -0.5 GPa have been successfully used as a stripline material for Nb/Al-AlO/sub x//Nb SIS junctions on fused quartz substrates.NbTiN is one of the most promising materials for use in the tuning circuits of Nb-based SIS mixers for operating frequencies above the gap frequency of Nb (/spl ap/700 GHz). We examine the properties of NbTiN films obtained using an unbalanced sputtering source in both RF and DC operating regimes. It is found that the properties of NbTiN films are strongly affected by the total pressure of the sputtering process. Films obtained under lower pressures have higher compressive stresses and lower resistivities. The best NbTiN films are obtained by DC sputtering and have a transition temperature of 14.4 K, a resistivity of 90 /spl mu//spl Omega//spl middot/cm at 20 K, and a compressive stress of -1 GPa. Films with a resistivity of 110 /spl mu//spl Omega//spl middot/cm at 20 K and a compressive stress of -0.5 GPa have been successfully used as a stripline material for Nb/Al-AlO/sub x//Nb SIS junctions on fused quartz substrates