Superconductors with periodically ordered mesoporous structures are expected to have properties very different from those of their bulk counterparts. Systematic studies of such phenomena to date are sparse, however, because of a lack of versatile synthetic approaches to such materials. We demonstrate the formation of three-dimensionally continuous gyroidal mesoporous niobium nitride (NbN) super...

We report on the fabrication of highly transparent superconductor/normal metal/two-dimensional electron gas junctions formed by a superconducting NbN electrode, a thin s10 nmd Au interlayer, and a two-dimensional electron gas in an InGaAs/ InP heterostructure. High junction transparency has been achieved by exploiting developed process of Au/NbN evaporation and rapid annealing at 400 °C. This a...

In this paper we present the development of low-noise waveguide mixers with NbN/AlN/NbN tunnel junctions at frequency approaching 1THz. The mixer was designed to be compatible with MgO substrate. Mixers of such a design demonstrated much improved receiver sensitivity. The improvement is a result of reduction of signal dissipation in waveguide and leakage into IF port by adopting a full-height w...

We report on unusual nonlinear dynamics observed in the resonance response of NbN superconducting microwave resonators. The nonlinear dynamics which occurs at relatively low input powers 2–4 orders of magnitude lower than Nb includes among others, jumps in the resonance line shape, hysteresis loops changing direction, and resonance frequency shift. These effects are measured herein using varyin...

Densities of states weighted with the diagonal matrix elements of two operators A and B, i.e., rho(A,B)(E)= summation operator(n)delta(E-E(n)), cannot, in general, be written as a trace formula, and therefore no simple extension of semiclassical trace formulas is known for this case. However, from the high resolution analysis of quantum spectra in the semiclassical regime we find stro...

The proposal of Elisa Marengo’s thesis is to extend commitment protocols to explicitly account for temporal regulations. This extension will satisfy two needs: (1) it will allow representing, in a flexible and modular way, temporal regulations with a normative force, posed on the interaction, so as to represent conventions, laws and suchlike; (2) it will allow committing to complex conditions, ...