Selective coupling of superconducting qubits via tunable stripline cavity

TL;DR

This paper proposes a tunable superconducting stripline cavity system for selective qubit coupling, enabling scalable quantum entanglement and universal gate operations while maintaining qubits at optimal coherence points.

Contribution

It introduces a method for selective qubit coupling using a tunable cavity with flux control, providing a scalable architecture for quantum information processing.

Findings

Derived an effective Hamiltonian for the two-qubit-cavity system.

Presented a protocol for Bell inequality measurements.

Discussed a composite pulse sequence for a universal control-phase gate.

Abstract

We theoretically investigate selective coupling of superconducting charge qubits mediated by a superconducting stripline cavity with a tunable resonance frequency. The frequency control is provided by a flux biased dc-SQUID attached to the cavity. Selective entanglement of the qubit states is achieved by sweeping the cavity frequency through the qubit-cavity resonances. The circuit is scalable, and allows to keep the qubits at their optimal points with respect to decoherence during the whole operation. We derive an effective quantum Hamiltonian for the basic, two-qubit-cavity system, and analyze appropriate circuit parameters. We present a protocol for performing Bell inequality measurements, and discuss a composite pulse sequence generating a universal control-phase gate.