Entanglement between more than two hundred macroscopic atomic ensembles in a solid

Area of Science:

• Quantum Physics
• Condensed Matter Physics

Background:

• Multipartite entanglement is crucial for quantum information processing but is challenging to create and verify in macroscopic systems.
• Dicke states represent a specific type of multipartite entanglement where a single excitation is distributed across multiple quantum systems.

Purpose of the Study:

• To experimentally generate and demonstrate multipartite entanglement in a macroscopic solid-state system.
• To investigate the creation of Dicke states using a single photon interacting with atomic ensembles.

Main Methods:

• Storing a single photon within a crystal containing multiple atomic ensembles with distinct resonance frequencies.
• Utilizing an interference effect, analogous to multi-slit diffraction, for controlled photon re-emission.
• Deriving a lower bound for the number of entangled ensembles based on interference contrast and single-photon purity.

Main Results:

• Successfully created a Dicke state distributed over a macroscopic ensemble.
• Experimentally demonstrated entanglement involving over 200 atomic ensembles, with each ensemble containing approximately one billion atoms.
• Showcased that individual atomic ensembles also exhibit internal entanglement.

Conclusions:

• The study provides a novel method for generating and verifying macroscopic multipartite entanglement.
• The demonstrated technique opens avenues for scalable quantum memory and quantum information processing applications.
• The findings highlight the potential for robust entanglement in large, solid-state quantum systems.