Merging diabolical points of a superconducting circuit

TL;DR

This paper theoretically investigates the merging of diabolical points in superconducting circuits, using an analytically solvable four-level model and applying it to a known Cooper pairs pump circuit.

Contribution

It introduces the first theoretical analysis of diabolical point merging in superconducting circuits, providing a model and applying it to a practical circuit.

Findings

Analytically solvable four-level model for diabolical point merging

Application to Cooper pairs pump circuit with known diabolical points

Foundational framework for future experimental studies

Abstract

We present the first theoretical study of the merging of diabolical points in the context of superconducting circuits. We begin by studying an analytically solvable four-level model which may serve as theoretical pattern for such a phenomenon. Then, we apply it to a circuit named Cooper pairs pump, whose diabolical points are already known.