Single-Period Floquet Control of Bosonic Codes with Quantum Lattice Gates

TL;DR

This paper introduces a fast, deterministic Floquet method for synthesizing unitaries in bosonic codes, enabling efficient quantum gate implementation and pseudorandom operations in continuous-variable quantum computing.

Contribution

It presents an analytical Floquet approach that synthesizes unitaries in a single period, bypassing slow adiabatic ramps, and demonstrates high-fidelity bosonic code operations using quantum lattice gates.

Findings

Reproduces Haar-random statistics in phase space

Achieves high-fidelity single-qubit gates on bosonic codes

Enables efficient continuous-variable quantum computing

Abstract

Bosonic codes constitute a promising route to fault-tolerant quantum computing. {Existing Floquet protocols enable analytical construction of bosonic codes but typically rely on slow adiabatic ramps with thousands of driving periods.} In this work, we circumvent this bottleneck by introducing an analytical and deterministic Floquet method that directly synthesizes arbitrary unitaries within a single period. The phase-space unitary ensembles generated by our approach reproduce the Haar-random statistics, enabling practical pseudorandom unitaries in continuous-variable systems. We prepare various prototypical bosonic codes from vacuum and implement single-qubit logical gates with high fidelities using quantum lattice gates. By harnessing the full intrinsic nonlinearity of Josephson junctions, quantum lattice gates decompose quantum circuits into primitive operations for efficient continuous-variable quantum computing.