Loh Lab | Research


Loh Lab @ CQT has traditionally been known for our focus on dipolar molecules. Afterall, dipolar molecules exhibit long-range anisotropic interactions that are useful for simulating interesting quantum phenomena like superconductivity and superfluidity, which are otherwise challenging to model on the microscopic scale with computers. These molecules are typically cooled and controlled in a bulk gas, so we have been focusing on developing new ways to cool and control these molecules with single-molecule resolution using “tweezer arrays”, which refer to arrays of optical tweezers formed from tightly focused laser beams.

A single molecule trapped in an optical tweezer

Since their invention in 1986, optical tweezers have remained a popular tool used by atomic physicists and biologists to trap atoms, molecules, and biological cells. The Nobel Prize in Physics was awarded in 2018 to Arthur Ashkin for his work on optical tweezers. The first demonstration of single atom trapping was performed by the Grangier group in 2001, and the extension to arrays of tweezers with the power of real time array reconfiguration was demonstrated by the Vuletic-Greiner-Lukin collaboration, the Browaeys group, and the Ahn group in 2016. Since then, tweezer arrays have become one of the hottest platforms worldwide for quantum simulation due to their relative scalability and ease of reconfigurability while maintaining quantum control of individual particles. (There are simply too many groups to be acknowledged here!) Beyond analog quantum simulation, several groups are also working towards digital quantum information processing.

Leveraging on our experience developed in the past few years, we are now starting a second experiment on tweezer arrays with Rydberg atoms. These atoms, like molecules, can still interact with each other through long-range dipolar interactions. Stay tuned for updates!

Read more about it:

The big deal about small building blocks (for the layman)

Previous research on cold and ultracold molecules in bulk gases (for the expert)