One-way quantum computation with two-photon multiqubit cluster states

TL;DR

This paper demonstrates the use of two-photon multiqubit cluster states for implementing a complete set of one-way quantum computation operations, including single-qubit rotations and two-qubit gates, with high fidelity.

Contribution

It introduces a method to realize one-way quantum computation using four-qubit cluster states entangled in polarization and momentum of two photons, showing practical implementation of key algorithms.

Findings

High fidelity in quantum operations achieved

Implementation of basic quantum algorithms like Grover's and Deutsch's

Cluster states of two photons are promising for scalable quantum computing

Abstract

We describe in detail the application of four qubit cluster states, built on the simultaneous entanglement of two photons in the degrees of freedom of polarization and linear momentum, for the realization of a complete set of basic one-way quantum computation operations. These consist of arbitrary single qubit rotations, either probabilistic or deterministic, and simple two qubit gates, such as a c-not gate for equatorial qubits and a universal c-phase (CZ) gate acting on arbitrary target qubits. Other basic computation operations, such as the Grover's search and the Deutsch's algorithms, have been realized by using these states. In all the cases we obtained a high value of the operation fidelities. These results demonstrate that cluster states of two photons entangled in many degrees of freedom are good candidates for the realization of more complex quantum computation operations based on a larger number of qubits.