Optically generated 2-dimensional photonic cluster state from coupled quantum dots

TL;DR

This paper presents a method to generate a 2D photonic cluster state using coupled quantum dots, enabling scalable quantum computing resources without strict frequency matching constraints.

Contribution

It combines existing 1D cluster state generation with a new optically induced CZ gate to create 2D cluster states from quantum dots.

Findings

Feasible with current technology.

No need for identical photon frequencies.

Potential to produce 2D photonic cluster sheets.

Abstract

We propose a method to generate a two-dimensional cluster state of polarization encoded photonic qubits from two coupled quantum dot emitters. We combine the recent proposal [N. H. Lindner and T. Rudolph, Phys. Rev. Lett. 103, 113602 (2009)] for generating 1-dimensional cluster state strings from a single dot, with a new proposal for an optically induced conditional phase (CZ) gate between the two quantum dots. The entanglement between the two quantum dots translates to entanglement between the two photonic cluster state strings. Further inter-pair coupling of the quantum dots using cavities and waveguides can lead to a 2-dimensional cluster sheet. Detailed analysis of errors indicates that our proposal is feasible with current tech- nology. Crucially, the emitted photons need not have identical frequencies, and so there are no constraints on the resonance energies for the quantum dots, a standard problem for such sources.