We propose to construct large quantum graph codes by means of superconducting circuits working at the ultrastrong coupling regime. In this physical scenario, we are able to create acluster state between any pair of qubits within a fraction of a nanosecond. To exemplify our proposal, creation of the five-qubit and Steane codes are demonstrated. We also provide optimal operating conditions with which the graph codes can be realized with state-of-the-art superconducting technologies.
Quantum networks play an important role in the implementation of quantum computing, communication and metrology. Circuit quantum electrodynamics (QED), consisting of superconductingartificial atoms coupled to on-chip resonators, provides a prime candidate to implement these networks due to their controllability and scalability. Furthermore, recent advances have also pushed the technology to the ultrastrong coupling (USC) regime of light-matter interaction, where the qubit-cavity coupling strength reaches a considerable fraction of the cavity frequency. Here, we propose the implementation of a scalable quantum random-access memory (QRAM) architecture based on a circuit QED network, whose edges operate in the USC regime. In particular, we study the storage and retrieval of quantum information in a parity-protected quantum memory and propose quantum interconnects in experimentally feasible schemes. Our proposal may pave the way for novel quantum memory applications ranging from entangled-state cryptography, teleportation, purification, fault-tolerant quantum computation, to quantum simulations.