A fully connected qubit network model for quantum information processing applications

Cheng Li Wu

Mark W. Coffey, Ron Deiotte

We present a scalable spin-1/2 network capable of performing calculations of interest to number theory. Among these computations are primality testing and factoring. The fully connected network model is realizable with superconducting phase qubits, and very probably with other solid-state spin implementations. The spin network model offers the prospect to perform interesting calculations in quantum information processing with a modest number of qubits.

Mark W. Coffey, Grant Allen

We present and prove identities for the eigenvalue degeneracy of a fully connected spin network with isotropic spin coupling. Such a network has application to quantum information processing, especially for solid-state implementations, and in fact the qubit case with anisotropic coupling has been recently realized. One set of proofs and other relations for the case of qubits is given in the context of hypergeometric summation. We then generalize to arbitrary spin, using combinatorial arguments.

Harry J. Kimble

Mark W. Coffey, Grant Allen

We present and prove identities for the eigenvalue degeneracy of a fully connected spin network with isotropic spin coupling.Such a network has application to quantum information processing, especially for solid-state implementations, and in fact the qubit case with anisotropic coupling has been recently realized.One set of proofs and other relations for the case of qubits is given in the context of hypergeometric summation.We then generalize to arbitrary spin, using combinatorial arguments.

Fang-Xiang Wang, Sheng-Teng Zheng, Long Huang +15 more

Fully connected quantum networks enable simultaneously connecting every user to every other user and are the most versatile and robust networking architecture. However, the scalability of such networks remains great challenge for practical applications. Here we construct a large-scale fully connected quantum network founded on two-photon Hong-Ou-Mandel (HOM) interference, where user-to-user security is guaranteed even with untrusted network provider. Using integrated soliton microcomb (SMC) and photonic encoding chips, we realize precise massive parallel frequency generation and locking, high-visibility HOM interferences and measurement-device-independent (MDI) quantum key distribution. The proposed architecture enables a 200-user fully connected quantum network over 200 kilometers with strict information-theoretic security via untrusted network provider. The implemented networking architecture paves the way for realizing large-scale fully connected MDI quantum networks across metropolitan and intercity regions.