High-fidelity Generation of Bell and W States in Giant Atom System via Bound State in the Continuum

TL;DR

This paper presents a robust method for high-fidelity entangled state generation in giant atom systems using bound states in the continuum, achieving over 98% fidelity and stability suitable for quantum information applications.

Contribution

It introduces a novel scheme leveraging bound states in the continuum for entanglement generation in giant atoms, surpassing traditional decoherence limitations.

Findings

Achieves over 98% fidelity in Bell state generation.

Extends scheme to generate W states in three-atom systems.

Produces stable entangled states in short time, resistant to decoherence.

Abstract

In this paper, we propose a high-fidelity scheme for generating entangled states in a system of two and three giant atoms coupled to the coupled resonator waveguide. Our approach leverages the bound state in the continuum, which is robust against waveguide disorder. Specifically, we achieve a fidelity exceeding $98\%$ for Bell state generation, overcoming the limitations of conventional decoherence-free interaction mechanisms. This scheme can be readily extended to a three-giant-atom system for generating W states. In both the two- and three-atom setups, the maximally entangled states are generated in a short time and remain stable even as time approaches infinity. Our proposal is feasible for implementation on state-of-the-art solid-state quantum platforms and significantly broadens the applications of giant atoms and waveguide QED system in quantum information processing.