Modular architectures to deterministically generate graph states

TL;DR

This paper introduces a modular quantum dot-based architecture for deterministic generation of complex graph states, enabling scalable photonic quantum computing with minimal optical switching and demonstrating fault-tolerance and loss correction capabilities.

Contribution

The authors propose a novel modular design that avoids two-qubit gates and reduces optical switching, advancing scalable and fault-tolerant photonic quantum state generation.

Findings

Achieves deterministic generation of N-dimensional cluster states.

Demonstrates a fault-tolerant quantum memory with 0.53% error threshold.

Provides bounds on correctable loss based on percolation theory.

Abstract

Graph states are a family of stabilizer states which can be tailored towards various applications in photonic quantum computing and quantum communication. In this paper, we present a modular design based on quantum dot emitters coupled to a waveguide and optical fiber delay lines to deterministically generate N-dimensional cluster states and other useful graph states such as tree states and repeater states. Unlike previous proposals, our design requires no two-qubit gates on quantum dots and at most one optical switch, thereby, minimizing challenges usually posed by these requirements. Furthermore, we discuss the error model for our design and demonstrate a fault-tolerant quantum memory with an error threshold of 0.53% in the case of a 3d graph state on a Raussendorf-Harrington-Goyal (RHG) lattice. We also provide a fundamental upper bound on the correctable loss in the fault-tolerant RHG state based on the percolation theory, which is 1.24 dB or 0.24 dB depending on whether the state is directly generated or obtained from a simple cubic cluster state, respectively.