High-efficiency cluster-state generation with atomic ensembles via the dipole-blockade mechanism

TL;DR

This paper proposes a theoretical scheme for efficiently generating cluster states using atomic ensembles and the dipole blockade mechanism, enabling scalable quantum computing resources.

Contribution

It introduces a novel protocol for high-efficiency entanglement of atomic ensembles to produce GHZ states for cluster state construction.

Findings

Single-step Q-qubit GHZ state generation with success probability ~ eta^{Q/2}

Significantly more efficient than previous probabilistic entangling methods

Utilizes atomic ensembles as single qubits with collective states

Abstract

We demonstrate theoretically a scheme for cluster state generation, based on atomic ensembles and the dipole blockade mechanism. In the protocol, atomic ensembles serve as single qubit systems. Therefore, we review single-qubit operations on qubit defined as collective states of atomic ensemble. Our entangling protocol requires nearly identical single-photon sources, one ultra-cold ensemble per physical qubit, and regular photodetectors. The general entangling procedure is presented, as well as a procedure that generates in a single step Q-qubit GHZ states with success probability p_success ~ eta^{Q/2}, where eta is the combined detection and source efficiency. This is significantly more efficient than any known robust probabilistic entangling operation. GHZ states form the basic building block for universal cluster states, a resource for the one-way quantum computer.