Tunable Chiral Bound States with Giant Atoms

TL;DR

This paper introduces tunable chiral bound states in superconducting giant atoms coupled to a Josephson photonic-crystal waveguide, enabling control over directionality and interactions for quantum simulation and topological phases.

Contribution

It presents a novel mechanism for creating tunable chiral bound states via nonlocal coupling in superconducting circuits, with potential for experimental realization.

Findings

Chiral bound states depend on atom-waveguide coupling and external bias.

Directional dipole-dipole interactions are achievable between giant atoms.

The system can be used to simulate topological phases and quantum phenomena.

Abstract

We propose tunable chiral bound states in a system composed of superconducting giant atoms and a Josephson photonic-crystal waveguide (PCW), with no analog in other quantum setups. The chiral bound states arise due to interference in the nonlocal coupling of a giant atom to multiple points of the waveguide. The chirality can be tuned by changing either the atom-waveguide coupling or the external bias of the PCW. Furthermore, the chiral bound states can induce directional dipole-dipole interactions between multiple giant atoms coupling to the same waveguide. Our proposal is ready to be implemented in experiments with superconducting circuits, where it can be used as a tunable toolbox to realize topological phase transitions and quantum simulations.