We present a tutorial on the principles of crystal growth of intermetallic and oxide compounds from molten solutions, with an emphasis on the fundamental principles governing the underlying phase equilibria and phase diagrams of multicomponent systems.
Results of resistivity, Hall effect, magnetoresistance, susceptibility and heat capacity measurements are presented for single crystals of indium-doped tin telluride with compositions Sn$_{.988-x}$In$_x$Te where $0 leq x leq 8.4 %$, along with micros
tructural analysis based on transmission electron microscopy. For small indium concentrations, $x leq 0.9 %$ the material does not superconduct above 0.3 K, and the transport properties are consistent with simple metallic behavior. For $x geq 2.7 %$ the material exhibits anomalous low temperature scattering and for $x geq 6.1 %$ bulk superconductivity is observed with critical temperatures close to 2 K. Intermediate indium concentrations $2.7% leq x leq 3.8%$ do not exhibit bulk superconductivity above 0.7 K. Susceptibility data indicate the absence of magnetic impurities, while magnetoresistance data are inconsistent with localization effects, leading to the conclusion that indium-doped SnTe is a candidate charge Kondo system, similar to thallium-doped PbTe.
Optimal control can be used to significantly improve multi-qubit gates in quantum information processing hardware architectures based on superconducting circuit quantum electrodynamics. We apply this approach not only to dispersive gates of two qubit
s inside a cavity, but, more generally, to architectures based on two-dimensional arrays of cavities and qubits. For high-fidelity gate operations, simultaneous evolutions of controls and couplings in the two coupling dimensions of cavity grids are shown to be significantly faster than conventional sequential implementations. Even under experimentally realistic conditions speedups by a factor of three can be gained. The methods immediately scale to large grids and indirect gates between arbitrary pairs of qubits on the grid. They are anticipated to be paradigmatic for 2D arrays and lattices of controllable qubits.
