General many-body entanglement swapping protocol: opportunities for distributed quantum computing

Abstract

Sharing entangled pairs between non-signaling parties via entanglement swapping constitutes a striking demonstration of the nonlocality of quantum mechanics and a crucial building block for future quantum technologies. In this work, we generalize pair-swapping methods by introducing a many-body entanglement swapping protocol, which allows two non-signaling parties to share general many-body states along an arbitrary partitioning. The shared many-body state retains exactly the same Schmidt vectors as the target state and exhibits typically high fidelity, which approaches unity as the variance of the Schmidt coefficients vanishes. Moreover, we demonstrate how the three-party protocol can be generalized to many-body swapping networks, enabling a general many-body state sharing with unit fidelity via arbitrary number of intermediate nodes. This is achieved by replacing all but one of the unitary operations with those corresponding to the same Schmidt states but with a flattened spectrum, which also completely eliminates the need for postselection. We provide a proof of concept of the three-party protocol on real quantum hardware and discuss how it enables new functionalities, such as fault-tolerant entanglement swapping and new strategies for distributed quantum computing.

15 pages, 7 figures

References in corpus (27)

• Quantum entanglement
• Quantum Computing in the NISQ era and beyond
• The Quantum Internet
• Area laws for the entanglement entropy - a review
• Quantum Error Correction for Quantum Memories
• Matrix Product States and Projected Entangled Pair States: Concepts, Symmetries, and Theorems
• Quantum error correction below the surface code threshold
• Quantum Entanglement Growth Under Random Unitary Dynamics
• Quantum repeaters: From quantum networks to the quantum internet
• Efficient long distance quantum communication
• Random Quantum Circuits
• High-threshold and low-overhead fault-tolerant quantum memory
• Experimental Nonlocality Proof of Quantum Teleportation and Entanglement Swapping
• Microwave Quantum Link between Superconducting Circuits Housed in Spatially Separated Cryogenic Systems
• Topological quantum computing with a very noisy network and local error rates approaching one percent
• Distributed Quantum Computing: a Survey
• Magic State Distillation: Not as Costly as You Think
• Challenges and Opportunities of Near-Term Quantum Computing Systems
• Experimental Realization of a Measurement-Induced Entanglement Phase Transition on a Superconducting Quantum Processor
• Long distance entanglement swapping with photons from separated sources
• Efficient Long-Range Entanglement using Dynamic Circuits
• Combining quantum processors with real-time classical communication
• Quantum Fourier Transform using Dynamic Circuits
• Sequential Quantum Circuits as Maps between Gapped Phases
• Beyond NISQ: The Megaquop Machine
• Complementarity and Information in "Delayed-choice for entanglement swapping"
• Information-disturbance trade-off in generalized entanglement swapping