Rotational Coherence Times of Polar Molecules in Optical Tweezers

Sean Burchesky; Loïc Anderegg; Yicheng Bao; Scarlett S Yu; Eunmi Chae; Wolfgang Ketterle; Kang-Kuen Ni; John M Doyle

doi:10.1103/PhysRevLett.127.123202

Rotational Coherence Times of Polar Molecules in Optical Tweezers

Phys Rev Lett. 2021 Sep 17;127(12):123202. doi: 10.1103/PhysRevLett.127.123202.

Authors

Sean Burchesky^{1

2}, Loïc Anderegg^{1

2}, Yicheng Bao^{1

2}, Scarlett S Yu^{1

2}, Eunmi Chae³, Wolfgang Ketterle^{2

4}, Kang-Kuen Ni^{1

2

5}, John M Doyle^{1

2}

Affiliations

¹ Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
² Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA.
³ Department of Physics, Korea University, Seongbuk-gu, Seoul 02841, South Korea.
⁴ Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
⁵ Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.

PMID: 34597100
DOI: 10.1103/PhysRevLett.127.123202

Abstract

Qubit coherence times are critical to the performance of any robust quantum computing platform. For quantum information processing using arrays of polar molecules, a key performance parameter is the molecular rotational coherence time. We report a 93(7) ms coherence time for rotational state qubits of laser cooled CaF molecules in optical tweezer traps, over an order of magnitude longer than previous systems. Inhomogeneous broadening due to the differential polarizability between the qubit states is suppressed by tuning the tweezer polarization and applied magnetic field to a "magic" angle. The coherence time is limited by the residual differential polarizability, implying improvement with further cooling. A single spin-echo pulse is able to extend the coherence time to nearly half a second. The measured coherence times demonstrate the potential of polar molecules as high fidelity qubits.