In this work, we develop a design methodology to generate spectrally pure photon pairs in asymmetric heterogeneously coupled waveguides by spontaneous parametric down-conversion. Mode coupling system of is used directly tailor the group velocity supermode achieve matching (GVM) that otherwise not allowed material dispersion. Design examples based on thin film lithium niobate are provided, demon...

The pair coupled cluster doubles (pCCD) method (where the excitation manifold is restricted to electron pairs) has a series of interesting features. Among others, it provides ground-state energies very close what obtained with doubly occupied configuration interaction (DOCI), but polynomial cost (compared exponential latter). Here, we address whether this similarity holds for excited states by ...

We consider a three-terminal system consisting of quantum dot strongly coupled to two superconducting reservoirs in the infinite-gap limit and weakly normal metal. Using real-time diagrammatic approach, we calculate dynamics proximity-induced pair amplitude on dot. find that after quench shows pronounced oscillations with frequency determined by coupling superconductors. In addition, it decays ...