Hybrid Quantum Computation

TL;DR

This paper introduces a hybrid quantum computation model combining unitary evolution and measurement-based approaches, enabling efficient implementation of complex gates and algorithms like Grover's search.

Contribution

It proposes a novel hybrid model that integrates unitary and measurement-based quantum computation, with detailed gate implementation and classical information processing methods.

Findings

Efficient simulation of complex gates using the hybrid model

Implementation of multi-control gates for Grover's algorithm

Classical information flow is simplified with flow vectors and matrices

Abstract

We present a hybrid model of the unitary-evolution-based quantum computation model and the measurement-based quantum computation model. In the hybrid model part of a quantum circuit is simulated by unitary evolution and the rest by measurements on star graph states, thereby combining the advantages of the two standard quantum computation models. In the hybrid model, a complicated unitary gate under simulation is decomposed in terms of a sequence of single-qubit operations, the controlled-Z gates, and multi-qubit rotations around the z-axis. Every single-qubit- and the controlled-Z gate are realized by a respective unitary evolution, and every multi-qubit rotation is executed by a single measurement on a required star graph state. The classical information processing in our model only needs an information flow vector and propagation matrices. We provide the implementation of multi-control gates in the hybrid model. They are very useful for implementing Grover's search algorithm, which is studied as an illustrating example.