Scalable W-type entanglement resource in neutral-atom arrays with Rydberg-dressed resonant dipole-dipole interaction

While the Rydberg-blockade regime provides the natural setting for creating W-type entanglement with cold neutral atoms, it is demonstrated here that a scalable entanglement resource of this type can even be obtained under completely different physical circumstances. To be more precise, a special instance of twisted W states-namely, pi-twisted ones-can be engineered in one-dimensional arrays of cold neutral atoms with Rydberg-dressed resonant dipole-dipole interaction. In particular, it is shown here that this is possible even when a (dressed) Rydberg excitation is coupled to the motional degrees of freedom of atoms in their respective, nearly harmonic optical-dipole microtraps, which are quantized into dispersionless (zero-dimensional) bosons. For a specially chosen (sweet-spot) detuning of the off-resonant dressing lasers from the relevant internal atomic transitions, the desired pi-twisted W state of Rydberg-dressed qubits is the ground state of the effective excitation-boson Hamiltonian of the system in a broad window of the relevant parameters. Being at the same time separated from the other eigenstates by a gap equal to the single-boson energy, this W state can be prepared using a Rabi-type driving protocol. The corresponding preparation times are independent of the system size and several orders of magnitude shorter than the effective lifetimes of the relevant atomic states.

Automated summary

This study demonstrates the creation of scalable entanglement resources in a different physical environment through the engineering of twisted W states in arrays of cold neutral atoms. By utilizing specific laser tuning and effective excitation-boson Hamiltonian, the desired W state can be prepared efficiently.