Tunable coupler to fully decouple and maximally localize superconducting qubits

Abstract

Enhancing the capabilities of superconducting quantum hardware, requires higher gate fidelities and lower crosstalk, particularly in larger scale devices, in which qubits are coupled to multiple neighbors. Progress towards both of these objectives would highly benefit from the ability to fully control all interactions between pairs of qubits. Here we propose a new coupler model that allows to fully decouple dispersively detuned Transmon qubits from each other, i.e. ZZ-crosstalk is completely suppressed while maintaining a maximal localization of the qubits' computational basis states. We further reason that, for a dispersively detuned Transmon system, this can only be the case if the anharmonicity of the coupler is positive at the idling point. A simulation of a 40ns CZ-gate for a lumped element model suggests that achievable process infidelity can be pushed below the limit imposed by state-of-the-art coherence times of Transmon qubits. On the other hand, idle gates between qubits are no longer limited by parasitic interactions. We show that our scheme can be applied to large integrated qubit grids, where it allows to fully isolate a pair of qubits, that undergoes a gate operation, from the rest of the chip while simultaneously pushing the fidelity of gates to the limit set by the coherence time of the individual qubits.

7 pages, 5 figures

References in corpus (5)

• Supplementary information for "Quantum supremacy using a programmable superconducting processor"
• Charge insensitive qubit design derived from the Cooper pair box
• QuTiP 2: A Python framework for the dynamics of open quantum systems
• Strong quantum computational advantage using a superconducting quantum processor
• Low-decoherence flux qubit

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• Machine learning of quantum channels on NISQ devices
• Capacitively Shunted Double-Transmon Coupler Realizing Bias-Free Idling and High-Fidelity CZ Gate
• Optimizing the frequency positioning of tunable couplers in a circuit QED processor to mitigate spectator effects on quantum operations
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• Transmon-assisted high-fidelity controlled-Z gates for integer fluxonium qubits
• The perfect entangler spectrum as a tool to analyze crosstalk
• Quantum Acoustics with Superconducting Qubits in the Multimode Transition-Coupling Regime
• On-chip microwave coherent source with in-situ control of the photon number distribution
• A Search for Classical Subsystems in Quantum Worlds