Ultrastrong coupling in a scalable design for circuit QED with superconducting flux qubits

TL;DR

This paper proposes a scalable circuit QED architecture with superconducting flux qubits achieving ultrastrong coupling by adjusting capacitance, enabling two-qubit interactions for quantum computing.

Contribution

It introduces a novel scalable design for circuit QED with flux qubits that achieves ultrastrong coupling and two-qubit interactions.

Findings

Ultrastrong coupling is achievable by varying capacitance.

The design supports scalable two-qubit coupling.

Theoretical analysis confirms the feasibility of the architecture.

Abstract

We theoretically study a circuit quantum electrodynamics (QED) architecture with superconducting flux qubits. The qubit is coupled to the transmission line resonator by an ac current originating from the current mode of the resonator. Ultrastrong coupling can be obtained by varying the capacitance between the qubit and the resonator. We propose a scalable design where the two-qubit coupling can be achieved.