Welcome to the ultracold atomic and molecular physics group in the Department of Physics and the James Franck Institute, at the University of Chicago. Here you will find a new and active research team exploring the quantum world at the lowest temperatures scientists can achieve, nearly a billionth of a degree Kelvin above absolute zero. Few sample images are shown in our Ultracold gallery. If you are interested in our research program or have any questions, please drop me a line, cchin @ uchicago.edu. I am looking forward to hearing from you!

Cheng Chin


Our paper, "Transition from an atomic to a molecular Bose–Einstein condensate" is published in Nature.

We create Bose-Einstein condensates (BECs) of spinning short-range molecules in a flat-bottomed two-dimensional trap by pairing atoms in an atomic BEC through a g-wave Feshbach resonance. The trap geometry and the low temperature of the molecules help to reduce inelastic loss, ensuring thermal equilibrium. From the equation-of-state measurement, we determine the molecular scattering length to be +220(± 30) Bohr radii (95% confidence interval). We also investigate the unpairing dynamics in the strong coupling regime and find that near the Feshbach resonance the dynamical timescale is consistent with the unitary limit. Our work demonstrates the long-sought transition between atomic and molecular condensates, the bosonic analogue of the crossover from a BEC to a Bardeen-Cooper-Schrieffer (BCS) superfluid in a Fermi gas.

This work is featured on UChicago News .


Our paper, "Pattern formation in a driven Bose–Einstein condensate" is published in Nature Physics.

We report that the density patterns with two- (D2), four- (D4) and six-fold (D6) symmetries can emerge in Bose–Einstein condensates on demand when the atomic interactions are modulated at multiple frequencies. The D6 pattern, in particular, arises from a resonant wave-mixing process that establishes phase coherence of the excitations that respect the symmetry. Our experiments explore a novel class of non-equilibrium phenomena in quantum gases, as well as a new route to prepare quantum states with desired correlations


Superresolution Microscopy


Our paper, "Superresolution Microscopy of Cold Atoms in an Optical Lattice" is published in Physical Review X.

We report on a new superresolution imaging technique which reveals the atomic density distribution of cold atoms in an optical lattice with a spatial resolution of 32 nm. The image above shows a byproduct of our scheme, mm-scale moire patterns that are immensely-magnified images of the single-site density distribution.

The work is featured in a Physics Viewpoint article "Zooming in on Ultracold Matter."



Our paper, "Observation of fermion-mediated interactions between bosonic atoms" is published in Nature!


For more information, please click the link above to read the paper, or the link in the box to read more about it from us! Thank you to Frankie Fung for the above illustration.

Coming soon...

Our Quantum Matter Synthesizer project received funding from the U.S. Department of Energy!

For more informaton, see the article in UChicago News.

Our paper, "Collective emission of matter-wave jets from driven Bose-Einstein condensates"  is published in Nature

We report an exciting observation that a rapid modulation of the interactions between atoms in a Bose-Einstein condensate leads to emission of atoms that forms jet structure. In the figure, the image on the far left is the original condensate, 15 micron in diameter. The 4 images on the right show the evolution of the sample during the emission process of about 20 ms.Click to see the videos of Bose Fireworks. More stories about this discovery see UChicago News.


Our paper, "Correlations in high-harmonic generation of matter-wave jets revealed by pattern recognition"  is published in Science.

We report the high harmonic generation of matterwave jets with a rapid modulation of the interactions between atoms in a Bose-Einstein condensate. By implementing a versatile pattern recongnition algoritm, we are able to identify a "turtle" pattern from seemingly random jet emission pattern. Such pattern reveals the underlying secondary scattering processes.

This story is also covered by UChicago News .

Levitation of particles

Our paper, "Stable thermophoretic trapping of generic particles at low pressures" is published in Applied Physics Letters!

Check it out at Appl. Phys. Lett. 110, 034102 (2017)

For more informaton, take a look at the article in UChicago News or our Undergraduate student research.

Quantum Matter Synthesizer

Quantum Matter Synthesizer

The Quantum Matter Synthesizer (QMS) is a new experimental platform for quantum simulations and engineering new quantum phases. Once completed, the QMS will be able to load atoms into a far-detuned lattice projected through a high numerical aperture objective lens, image the atomic distribution and cool the atoms to the vibrational ground state, and then dynamically turn off and rearrange lattice sites to achieve the desired filling fraction and spin order. We will achieve this dynamically re-arrangeable lattice by forming our 2D optical potential with Digital Micromirror Devices (DMD).Read More