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Long Rotational Coherence Times of Molecules in a Magnetic Trap
L Caldwell1, H J Williams1, N J Fitch1
1Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom.
Physical Review Letters
|February 29, 2020
Summary
Researchers found specific molecular transitions insensitive to magnetic fields, enabling longer coherence times for trapped polar molecules. This breakthrough advances quantum technologies by preserving delicate quantum states.
Area of Science:
- Quantum physics
- Molecular physics
- Laser cooling
Background:
- Trapped polar molecules offer long-range dipolar interactions crucial for quantum applications.
- Maintaining quantum coherence in these molecules within traps is a significant experimental challenge.
Purpose of the Study:
- To identify laser-coolable molecules with rotational transitions insensitive to magnetic fields.
- To experimentally demonstrate extended rotational coherence times in trapped molecules.
Main Methods:
- Theoretical calculations to identify suitable molecular transitions.
- Experimental verification using calcium fluoride (CaF) molecules in a magnetic trap.
- Measurement of transition sensitivity and rotational coherence time.
Main Results:
- Identified numerous laser-coolable molecules with magnetic-field-insensitive rotational transitions.
- Verified a CaF transition with sensitivity below 5 Hz/G.
- Achieved a rotational coherence time of 6.4(8) ms in a magnetic trap.
Conclusions:
- Molecular rotational transitions can be engineered for high magnetic field insensitivity.
- Extended coherence times are achievable for trapped polar molecules, paving the way for quantum information processing.
- Simulations indicate potential for coherence times exceeding 1 second.
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