Coherence of Symmetry-Protected Rotational Qubits in Cold Polyatomic Molecules

Area of Science:

• Quantum information science
• Molecular physics
• Cold atom physics

Background:

• Polar polyatomic molecules offer unexplored potential for encoding qubits in rotational states.
• Developing robust qubits is crucial for advancing quantum computing and precision measurements.

Purpose of the Study:

• To explore the use of cold polar molecules as a platform for quantum information processing.
• To demonstrate a novel qubit encoded in the rotational states of formaldehyde (H₂CO).

Main Methods:

• Trapping cold formaldehyde molecules (100-600 mK) within an electric trap.
• Performing Ramsey-type experiments to observe molecular coherences.

Main Results:

• Observed long-lived coherences (∼100 μs) between symmetry-protected molecular states.
• Demonstrated a qubit with opposite rotation but identical orientation, a quasi-hidden molecular degree of freedom.
• The qubit exhibited insensitivity to electric fields and weak dependence on magnetic fields.

Conclusions:

• Cold polar molecules, specifically formaldehyde, can serve as robust qubits.
• The demonstrated qubit properties are advantageous for future quantum and precision measurement applications.
• This work opens new avenues for utilizing molecular rotational states in quantum technologies.