Entanglement transfer between giant atoms in waveguide-QED systems

TL;DR

This paper explores how entanglement can be transferred between giant atoms in waveguide-QED systems, revealing that braided configurations enable near-perfect transfer, outperforming other configurations and small atoms.

Contribution

It introduces and compares different coupling configurations of giant atoms, demonstrating the superior entanglement transfer capabilities of the braided configuration.

Findings

Braided configuration achieves complete entanglement transfer.

Entanglement transfer efficiency depends strongly on phase shift.

Giant atoms outperform small atoms in entanglement transfer.

Abstract

We investigate the entanglement transfer between giant atoms in waveguide-QED systems. The system consists of two pairs of two-level giant atoms, $ab$ and $cd$, each independently coupled to its respective one-dimensional waveguide. Initially, entangled states are stored in atom pair $ac$. There we consider three giant atom coupling configurations: separated, braided, and nested. For comparison, the entanglement transfer for small atoms configuration is also studied here. We focus on the entanglement transfer from atom pair $ac$ to atoms pair $bd$ and atom pair $ab$ in these four coupling configurations. It is shown that the transfer of entanglement in each coupling configuration strongly depends on phase shift. In particular, the braided configuration demonstrates superior performance in entanglement transfer. For the entanglement transfer from atom pair $ac$ to atom pair $bd$, complete entanglement transfer is presented in braided configuration, a behavior not found in small atom or other giant atom configurations. For the entanglement transfer from atom pair $ac$ to atom pair $ab$, although the maximum entanglement transferred to atom pair $ab$ in the braided configuration is half of that one to atom pair $bd$, it is still higher than that in the small atom, separated, and nested configurations. This study lays the foundation for entanglement transfer between giant atoms in waveguide-QED platforms.