Imperfect-interaction-free entanglement purification on stationary systems for solid quantum repeaters.

Area of Science:

• Quantum Information Science
• Quantum Networking
• Solid-State Quantum Systems

Background:

• Solid quantum repeaters are essential for building large-scale quantum networks.
• Entanglement purification is crucial for quantum repeaters to distill high-fidelity entanglement and mitigate noise.
• Existing methods face challenges with imperfect interactions and noise in realistic conditions.

Purpose of the Study:

• To present an imperfect-interaction-free entanglement purification scheme for nonlocal electron spins in quantum dots.
• To enhance the fidelity of nonlocal entanglement for solid quantum repeaters.
• To relax experimental requirements for practical quantum network implementation.

Main Methods:

• Utilizing a faithful parity check on electron spins within quantum dots.
• Implementing entanglement purification under nearly realistic conditions with imperfect light-matter interaction.
• Employing quantum dots embedded inside a microcavity interacting with circularly polarized photons.

Main Results:

• Demonstrated successful parity determination without destroying nonlocal solid entanglement, even with imperfect interactions.
• Prevented maximally entangled states from degrading into partially entangled states.
• Guaranteed the fidelity of nonlocal mixed states to a desired level post-purification.

Conclusions:

• The proposed imperfect-interaction-free entanglement purification scheme is feasible under realistic conditions.
• This technique offers a practical approach to improving entanglement quality for solid quantum repeaters.
• The relaxed experimental requirements pave the way for more accessible large-scale quantum networks.