Tunable ion-photon entanglement in an optical cavity

Area of Science:

• Quantum Information Science
• Atomic, Molecular, and Optical Physics

Background:

• Quantum networks require robust quantum interfaces for light-matter interaction and precise control of quantum states.
• Previous methods for entangling photons and quantum memories were limited by fixed transition parameters or required pre-prepared superposition states.

Purpose of the Study:

• To develop a fully tunable method for creating entanglement between a single ion and a single photon.
• To enable deterministic, high-fidelity generation of arbitrary two-qubit entangled states for quantum networking.

Main Methods:

• Utilized a single (40)Ca(+) ion within an optical resonator.
• Employed a bichromatic, cavity-mediated Raman transition to couple the ion's state to a photon's polarization.
• Adjusted relative phase and amplitude of two selected coupling paths.

Main Results:

• Achieved fully tunable entanglement between a single (40)Ca(+) ion and the polarization of a single photon.
• Demonstrated deterministic, high-fidelity generation of any two-qubit entangled state.
• The cavity setting intrinsically facilitated the control over entanglement parameters.

Conclusions:

• The developed bichromatic Raman transition method offers a promising approach for creating versatile quantum interfaces.
• This technique is applicable to various quantum memory systems, paving the way for advanced quantum networks.