[Paper Review] A Layered Architecture for Quantum Computing Using Quantum Dots

N. Cody Jones, Rodney Van Meter+5 more|arXiv (Cornell University)|Oct 24, 2010

Quantum Computing Algorithms and Architecture94 references37 citations

TL;DR

This paper proposes a layered, modular quantum computing architecture using optically controlled quantum dots, leveraging electron spin states for qubit storage and ultrafast optical pulses for control. It demonstrates fault tolerance via a topological surface code, enabling Shor’s factoring algorithm for a 2048-bit number to be executed in approximately one week, with scalability and integration advantages from semiconductor fabrication.

ABSTRACT

We address the challenge of designing a quantum computer architecture with a layered framework that is modular and facilitates faulttolerance. The framework is flexible and could be used for analysis and comparison of differing quantum computer designs. Using this framework, we develop a complete, layered architecture for quantum computing with optically controlled quantum dots, showing how a myriad of technologies must operate synchronously to achieve fault-tolerance. Our design deliberately takes advantage of the large possibilities for integration afforded by semiconductor fabrication. Quantum information is stored in the electron spin states of a charged quantum dot controlled by ultrafast optical pulses. Optical control makes this system very fast, scalable to large problem sizes, and extensible to quantum communication or distributed architectures. The design of this quantum computer centers on error correction in the form of a topological surface code, which requires only local and nearest-neighbor gates. We analyze several important issues of the surface code that are relevant to an architecture, such as resource accounting and the use of Pauli frames. Furthermore, we investigate the performance of this system and find that Shor’s factoring algorithm for a 2048-bit number can be executed in approximately one week. PACS numbers: 03.67.Pp, 03.67.Lx, 85.35.Be, 73.21.La, 85.40.Hp

Motivation & Objective

• To design a modular, fault-tolerant quantum computing architecture that supports scalable and extensible quantum computation.
• To enable fault tolerance through implementation of the topological surface code with only local and nearest-neighbor operations.
• To leverage semiconductor fabrication for high integration density and system scalability.
• To analyze critical architectural challenges such as resource accounting and Pauli frame management in surface code implementations.
• To evaluate system performance for a practical quantum algorithm, specifically Shor’s factoring algorithm.

Proposed method

• Employing electron spin states in charged quantum dots as qubits, with ultrafast optical pulses for coherent control and initialization.
• Designing a layered architecture that integrates qubit control, error correction, and classical control systems in a hierarchical framework.
• Implementing the surface code for fault tolerance, relying on local and nearest-neighbor two-qubit gates to minimize error propagation.
• Using Pauli frames to reduce classical processing overhead in error correction cycles.
• Applying resource accounting to estimate the number of physical qubits and operations required for fault-tolerant logical qubits.
• Integrating optical control for high-speed operations and enabling potential extension to quantum communication and distributed architectures.

Experimental results

Research questions

• RQ1 How can a scalable and modular quantum architecture be designed using optically controlled quantum dots?
• RQ2 What are the key architectural challenges in implementing the surface code for fault-tolerant quantum computation?
• RQ3 How can resource accounting and Pauli frame techniques be effectively integrated into a physical quantum architecture?
• RQ4 What is the estimated performance of the system for executing Shor’s factoring algorithm on a 2048-bit number?
• RQ5 To what extent can semiconductor fabrication techniques enable integration and scalability in this quantum computing platform?

Key findings

• The proposed architecture achieves fault tolerance using the surface code with only local and nearest-neighbor two-qubit gates, minimizing complex control requirements.
• Resource accounting shows that the system can support fault-tolerant logical qubits with a feasible number of physical qubits and operations.
• Pauli frame techniques are effective in reducing classical processing overhead during error correction cycles.
• The system enables high-speed operation due to ultrafast optical control, supporting fast gate operations critical for algorithmic performance.
• Shor’s factoring algorithm for a 2048-bit number can be executed in approximately one week, demonstrating practical feasibility for large-scale quantum computation.
• The integration potential of semiconductor fabrication allows for scalability and extension to distributed quantum architectures or quantum communication networks.