Mode engineering with a one-dimensional superconducting metamaterial

TL;DR

This paper introduces a method to control the Josephson energy in superconducting metamaterials by engineering electromagnetic modes through spatial modulation of the loop's parameters, enabling tunable quantum device properties.

Contribution

It demonstrates how mode engineering via inhomogeneous superconducting loops can effectively tune Josephson energy, a novel approach for quantum circuit design.

Findings

Josephson energy can be increased or decreased by mode engineering.

Spatial modulation of inductance and capacitance affects mode spectrum.

Mode engineering is feasible with current superconducting metamaterials.

Abstract

We propose a way to control the Josephson energy of a single Josephson junction embedded in one- dimensional superconducting metamaterial: an inhomogeneous superconducting loop, made out of a superconducting nanowire or a chain of Josephson junctions. The Josephson energy is renormalized by the electromagnetic modes propagating along the loop. We study the behaviour of the modes as well as of their frequency spectrum when the capacitance and the inductance along the loop are spatially modulated. We show that, depending on the amplitude of the modulation, the renormalized Josephson energy is either larger or smaller than the one found for a homogeneous loop. Using typical experimental parameters for Josepshon junction chains and superconducting nanowires, we conclude that this mode-engineering can be achieved with currently available metamaterials.