Building Block For Universal Continuous Variables Computation In Superconducting Devices

TL;DR

This paper proposes a scalable superconducting architecture for universal continuous variable quantum computation, demonstrating high-fidelity implementation of all essential gates within accessible experimental regimes.

Contribution

It introduces a novel two-layer superconducting design that enables all five universal CV gates with high fidelity, advancing towards scalable CV quantum computing.

Findings

Achieves ≥98% fidelity for all CV gates within current experimental parameters.

Design employs a DC-SQUID, fluxonium qubit, and ancillary qubits for versatile operations.

Modular architecture facilitates straightforward scaling for universal CV quantum computation.

Abstract

Continuous variable (CV) quantum computation offers an alternative to qubit-based computing by exploiting the infinite-dimensional Hilbert space of bosonic modes. Despite recent progress, superconducting platforms have yet to demonstrate a scalable architecture capable of universal computation. Here, we design and numerically simulate a two-layer superconducting architecture that implements all five interactions of the universal CV gate set (rotation, displacement, squeezing, Kerr, and beam splitter) within experimentally accessible regimes. To this end, we employ a DC-SQUID as the bosonic mode, a fluxonium qubit to mediate nonlinear interactions, and two ancillary qubits that enable Gaussian and multi-mode operations. By tuning fluxes and frequencies, we achieve high fidelities ($\geq 98\%$) across all gates within state-of-the-art parameter ranges. The modular nature of the design allows straightforward scaling, establishing a feasible pathway toward high-fidelity, universal CV quantum computation based on superconducting circuits.