Low error measurement-free phase gates for qubus computation

TL;DR

This paper introduces a measurement-free, low-error two-qubit phase gate for quantum computation using a coherent bus mode and cross-Kerr interactions, improving robustness and determinism over previous methods.

Contribution

It presents a novel deterministic phase gate method that is measurement-free, robust against parameter variations, and applicable to solid state and photonic qubits.

Findings

The proposed gate achieves low error rates.

The method is robust against parameter variations.

It is applicable to both solid state and photonic qubit systems.

Abstract

We discuss the desired criteria for a two-qubit phase gate and present a method for realising such a gate for quantum computation that is measurement-free and low error. The gate is implemented between qubits via an intermediate bus mode. We take a coherent state as the bus and use cross-Kerr type interactions between the bus and the qubits. This new method is robust against parameter variations and is thus low error. It fundamentally improves on previous methods due its deterministic nature and the lack of approximations used in the geometry of the phase rotations. This interaction is applicable both to solid state and photonic qubit systems.