Blind quantum computing with weak coherent pulses.

Area of Science:

• Quantum Information Science
• Quantum Cryptography
• Computational Complexity

Background:

• Universal Blind Quantum Computation (UBQC) enables secure remote quantum computation.
• Ideal UBQC requires clients to generate specific, random single qubit states for perfect privacy.
• Practical limitations hinder perfect state generation and transmission over long distances.

Purpose of the Study:

• To introduce and define the concept of epsilon (ϵ) blindness for UBQC protocols.
• To quantify the robustness and security of UBQC under realistic imperfections.
• To develop a practical protocol for preparing quantum states suitable for ϵ-blind UBQC.

Main Methods:

• Formalized ϵ blindness by analogy to ϵ security in cryptography.
• Developed a remote blind single qubit preparation protocol using weak coherent pulses.
• Analyzed the protocol's performance in arbitrarily lossy quantum channels.

Main Results:

• Demonstrated that ϵ blindness characterizes UBQC security under imperfections.
• Achieved efficient preparation of quantum states arbitrarily close to ideal random states.
• Enabled ϵ-blind UBQC for any ϵ > 0, even with significant channel loss.

Conclusions:

• The concept of ϵ blindness provides a robust framework for analyzing UBQC security.
• The proposed remote preparation protocol offers a practical solution for achieving delegated quantum computation.
• This work significantly enhances the feasibility and security of blind quantum computation in real-world scenarios.