A unified approach to realize universal quantum gates in a coupled two-qubit system with fixed always-on coupling

Abstract

We demonstrate that in a coupled two-qubit system any single-qubit gate can be decomposed into two conditional two-qubit gates and that any conditional two-qubit gate can be implemented by a manipulation analogous to that used for a controlled two-qubit gate. Based on this we present a unified approach to implement universal single-qubit and two-qubit gates in a coupled two-qubit system with fixed always-on coupling. This approach requires neither supplementary circuit or additional physical qubits to control the coupling nor extra hardware to adjust the energy level structure. The feasibility of this approach is demonstrated by numerical simulation of single-qubit gates and creation of two-qubit Bell states in rf-driven inductively coupled two SQUID flux qubits with realistic device parameters and constant always-on coupling.

4 pages, 3 figures

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Cited by in corpus (4)

• Variational generalized rotating-wave approximation in the two-qubit quantum Rabi model
• Single-step controlled-NOT logic from any exchange interaction
• Scalable quantum computation architecture using always-on Ising interactions via quantum feedforward
• Quantum entanglement of two flux qubits induced by an auxiliary SQUID