Quantum Fanout Gates in Constant Depth via Resonance Engineering

TL;DR

This paper introduces a resonance engineering-based method to implement an n-qubit fanout gate in constant depth, achieving linear infidelity scaling and enabling efficient simulation up to 100 qubits.

Contribution

It proposes a novel resonance engineering approach for quantum fanout gates with theoretical error bounds and scalable simulation techniques.

Findings

Linear infidelity scaling in constant time for the proposed gate.

Simulation of up to 100 qubits using permutation symmetry.

Performance consistent with theoretical error bounds.

Abstract

We present a novel implementation of an n-qubit fanout gate using resonance engineering. Our proposed mechanism uses Jaynes-Cummings interactions between multiple qubits and a common harmonic oscillator to realize a fanout gate at the system-level. Our theoretical analysis establishes upper bounds on the gate error, demonstrating linear infidelity scaling in constant time -- a favorable trade-off compared to a conventional CNOT decomposition. To validate the performance of our scheme at large system sizes, we exploit permutation symmetry to reduce the simulation complexity from exponential to polynomial in the number of qubits, enabling simulation up to 100 qubits. The results of this numerical analysis are consistent with our theoretical findings and allow us to characterize the performance well. Our gate will enable faster stabilizer readouts and could provide polynomial speedups in many quantum algorithms.