Quantum-Memory-Enhanced Preparation of Nonlocal Graph States
Abstract
Graph states are an important class of multipartite entangled states. Previous experimental generation of graph states and in particular the Greenberger-Horne-Zeilinger (GHZ) states in linear optics quantum information schemes is subjected to an exponential decay in efficiency versus the system size, which limits its large-scale applications in quantum networks. Here, we demonstrate an efficient scheme to prepare graph states with only a polynomial overhead using long-lived atomic quantum memories. We generate atom-photon entangled states in two atomic ensembles asynchronously, retrieve the stored atomic excitations only when both sides succeed, and further project them into a four-photon GHZ state. We measure the fidelity of this GHZ state and further demonstrate its applications in the violation of Bell-type inequalities and in quantum cryptography. Our work demonstrates the prospect of efficient generation of multipartite entangled states in large-scale distributed systems with applications in quantum information processing and metrology.
- Publication:
-
Physical Review Letters
- Pub Date:
- February 2022
- DOI:
- 10.1103/PhysRevLett.128.080501
- arXiv:
- arXiv:2202.13386
- Bibcode:
- 2022PhRvL.128h0501Z
- Keywords:
-
- Quantum Physics;
- Physics - Atomic Physics;
- Physics - Optics
- E-Print:
- Phys. Rev. Lett. 128, 080501 (2022)