Abstract: A modular quantum entanglement processing system can include a plurality of seed state systems, resource state systems, and fusion systems that can be ordered in different arrangements. The systems can be composed of modular assemblies or chips, such that the systems can be modularized and extended to perform entanglement based processing of tasks in a scalable manner. Some of the assemblies or chips of the different systems can be designed to operate at cryogenic temperatures, such as detector, while other assemblies or chips of the different systems can operate at room temperature, where the different chip types can be coupled to one another using fiber optic cables.

Abstract: Circuits are provided that create entanglement among qubits having Gottesman-Kitaev-Preskill (GKP) encoding using photonic systems and structures. For example, networks of beam splitters and homodyne measurement circuits can be used to perform projective entangling measurements on GKP qubits from different quantum systems. In some embodiments. GKP qubits can be used to implement quantum computations using fusion-based quantum computing or other fault-tolerant quantum computing approaches.