Deterministic photon source of genuine three-qubit entanglement.

Area of Science:

• Quantum Optics
• Quantum Information Science
• Solid-State Physics

Background:

• Deterministic single-photon sources are crucial for advancing quantum optics and quantum information processing.
• Entanglement generation, particularly multi-photon entanglement, is a key challenge for scalable quantum technologies.
• Quantum dots offer a promising platform for integrated quantum devices due to their tunable optical properties and scalability.

Purpose of the Study:

• To demonstrate a scalable, deterministic source of multi-photon entanglement.
• To achieve high-fidelity generation of entangled states using a single quantum emitter.
• To explore the potential of quantum dots in nanophotonic waveguides for quantum computing and networking.

Main Methods:

• Utilized a single electron spin trapped in a quantum dot embedded within a planar nanophotonic waveguide.
• Implemented nuclear spin narrowing to enhance the spin dephasing time to nanosecond timescales.
• Employed a spin-echo pulse sequence for the sequential generation of spin-photon and spin-photon-photon entanglement.

Main Results:

• Demonstrated a deterministic source of three-qubit entanglement.
• Achieved high-fidelity coherent optical spin rotations due to increased spin dephasing time.
• Generated highly indistinguishable photons, a critical factor for scalability and photon fusion.

Conclusions:

• Presented a scalable and deterministic approach for generating multi-photon entanglement.
• The developed source shows significant promise for applications in photonic quantum computing and quantum networks.
• The methodology provides a clear pathway for further improvements in entanglement generation and scalability.