Arbitrary Multi-Qubit Generation

TL;DR

This paper introduces a scheme for generating arbitrary multi-qubit quantum states using linear optics and heralding, applicable with current technology for small numbers of qubits, and analyzes its efficiency and robustness.

Contribution

It presents a novel method for multi-qubit state generation in quantum optics that is feasible with existing technology and extends to arbitrary qubit numbers with connections to boson sampling.

Findings

High success probability for small qubit numbers

Effective analysis of imperfections and inefficiencies

Potential for scalable multi-qubit state preparation

Abstract

We propose and analyse a scheme for single-rail-encoded arbitrary multi-qubit quantum-state generation to provide a versatile tool for quantum optics and quantum information applications. Our scheme can be realized, for small numbers of qubits, with current technologies using single photon inputs, passive linear optics, and heralding measurements. The particular examples of two- and three-qubit cluster states are studied in detail. We show that such states can be prepared with a high probability of success. Our analysis quantifies the effects of experimentally relevant imperfections and inefficiencies. The general case of arbitrary N-qubit preparation is discussed and some interesting connections to the boson sampling problem are given.