Collectively Encoded Rydberg Qubit

Area of Science:

• Quantum Information Science
• Atomic Physics
• Quantum Computing

Background:

• Quantum computation requires robust qubits resistant to environmental noise.
• Collective encoding in atomic ensembles offers a potential pathway for enhanced qubit stability.

Purpose of the Study:

• To demonstrate a collectively encoded qubit using Rydberg excitations in entangled atomic ensembles.
• To investigate the coherence and robustness of this qubit against perturbations and atom loss.

Main Methods:

• Utilizing a single Rydberg excitation stored in an ensemble of N entangled atoms.
• Performing qubit rotations via microwave fields driving Rydberg state excitations.
• Implementing coherent readout by mapping excitation to a single photon.
• Employing Ramsey interferometry to probe qubit coherence and robustness.

Main Results:

• Demonstrated preserved qubit coherence and Ramsey fringe visibility despite atom loss from the polariton mode.
• Quantified dephasing due to electric field noise, showing a fourth-power scaling with field amplitude.
• Confirmed the robustness of the collectively encoded qubit to external perturbations.

Conclusions:

• Collective encoding using Rydberg polaritons enables robust quantum information processing.
• This system presents an attractive alternative coding strategy for quantum computation and networking.
• The demonstrated qubit stability opens avenues for advanced quantum technologies.