Entangling transmons with low-frequency protected superconducting qubits

Abstract

Novel qubits with intrinsic noise protection constitute a promising route for improving the coherence of quantum information in superconducting circuits. However, many protected superconducting qubits exhibit relatively low transition frequencies, which could make their integration with conventional transmon circuits challenging. In this work, we propose and study a scheme for entangling a tunable transmon with a Cooper-pair parity-protected qubit, a paradigmatic example of a low-frequency protected qubit that stores quantum information in opposite Cooper-pair parity states on a superconducting island. By tuning the external flux on the transmon, we show that non-computational states can mediate a two-qubit entangling gate that preserves the Cooper-pair parity independent of the detailed pulse sequence. Interestingly, the entangling gate bears similarities to a controlled-phase gate in conventional transmon devices. Hence, our results suggest that standard high-precision gate calibration protocols could be repurposed for operating hybrid qubit devices.

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Cited by in corpus (14)

• The Josephson diode effect in supercurrent interferometers
• Parity-conserving Cooper-pair transport and ideal superconducting diode in planar Germanium
• Nonsinusoidal current-phase relations in semiconductor-superconductor-ferromagnetic insulator devices
• Charge-4e supercurrent in a two-dimensional InAs-Al superconductor-semiconductor heterostructure
• Multi-mode architectures for noise-resilient superconducting qubits
• Interfering Josephson diode effect in Ta2Pd3Te5 asymmetric edge interferometer
• Quantum circuits with multiterminal Josephson-Andreev junctions
• Dissipationless Nonlinearity in Quantum Material Josephson Diodes
• Subgap states in semiconductor-superconductor devices for quantum technologies: Andreev qubits and minimal Majorana chains
• Fermionic Quantum Simulation on Andreev Bound State Superlattices
• Josephson tunnel junction arrays and Andreev weak links: linked by a single energy-phase relation
• Parity-protected superconducting qubit based on topological insulators
• Optimal quantum resource generation in coupled transmons immersed in Markovian baths
• Gate- and flux-tunable sin(2$\phi$) Josephson element with proximitized Ge-based junctions