Columbia University scientists have created the first Bose-Einstein condensate from molecules, achieving temperatures near absolute zero and opening doors to new quantum simulations and materials science.
In a historic leap for quantum physics, physicists led by Sebastian Will at Columbia University have successfully produced a Bose-Einstein condensate (BEC) using sodium-cesium molecules. This achievement marks the first time such a molecular BEC has been realized, pushing beyond the limitations of atomic BECs that dominated since their 1995 discovery.
The condensate formed at approximately 5 nanoKelvin — colder than minus 459.66 degrees Fahrenheit — and lasted about two seconds, an unusually long duration for such experiments. The system was created using a combination of laser cooling, magnetic manipulation, and groundbreaking microwave shielding techniques developed in collaboration with theoretical physicist Tijs Karman at Radboud University in the Netherlands.
“This is an exciting achievement, but it’s really just the beginning,” said Will. “Molecular Bose-Einstein condensates open up whole new areas of research, from understanding truly fundamental physics to advancing powerful quantum simulations.”
A Century-Old Dream Realized Through Modern Control
The concept of a BEC traces back to Satyendra Nath Bose and Albert Einstein’s theoretical predictions in 1924–1925. For decades, the idea remained theoretical until 1995 when researchers successfully created BECs from atoms — work later recognized with the 2001 Nobel Prize in Physics.
But molecules posed a far greater challenge. Their internal motion and tendency to collide destructively made them difficult to cool below critical thresholds. Even the most chemically stable molecules often exhibited lifetimes too short for evaporation cooling to succeed.
Significant progress came in 2008 when Deborah Jin and Jun Ye cooled potassium-rubidium molecules to around 350 nanoKelvin. Yet true molecular BECs required temperatures far lower — a goal that seemed out of reach until now.
Why Molecules Were So Hard to Cool
Evaporative cooling — the process used to achieve BECs — relies on letting the most energetic particles escape first, gradually lowering the sample’s temperature. With molecules, however, collisions often resulted in chemical reactions or recombination events that destroyed the sample before it could be sufficiently cooled.
Fermionic molecules showed some promise due to quantum statistics reducing clustering tendencies. Bosonic molecules like sodium-cesium, however, tended to “bunch” together — increasing collision rates and making shielding essential.
“We’ve come up with schemes to control interactions, tested these in theory, and implemented them in the experiment,” said Karman. “It’s been really an amazing experience to see these ideas for microwave ‘shielding’ being realized in the lab.”
Microwave Shielding: The Key Innovation
The Columbia team leveraged microwave fields to create an effective “shield” around each molecule. By dressing molecules with electromagnetic fields, they altered how molecules interacted at close range — turning attractive forces into repulsive ones to prevent collisions.
Early experiments used a single microwave field, which reduced two-body losses but inadvertently increased three-body losses due to long-range attraction. The breakthrough came with adding a second microwave field — one circularly polarized and one linearly polarized — to cancel long-range attraction while preserving close-range repulsion.
“This was fantastic closure for me,” said Niccolò Bigagli, who completed his PhD this spring and helped launch the lab’s effort. “We went from not having a lab set up yet to these fantastic results.”
What the Molecular BEC Makes Possible
The experiment began with roughly 30,000 sodium-cesium molecules cooled over three seconds to reach the few-nanoKelvin range. During evaporation, condensation appeared once quantum degeneracy was reached — with more than 2,000 molecules near transition. Final condensates contained about 200 molecules.
“That will really let us investigate open questions in quantum physics,” said co-first author Siwei Zhang. “By controlling these dipolar interactions, we hope to create new quantum states and phases of matter,” added postdoc Ian Stevenson.
Ye, who led the 2008 milestone at JILA, called the new work “a high level achievement.” “Will’s experiment features precise control of molecular interactions to steer the system toward a desired outcome, a marvelous achievement in quantum control technology.”
Practical Implications and Future Directions
This molecular BEC enables researchers to test theories about materials whose behavior depends on strong, long-range interactions — including exotic quantum phases resistant to conventional computational methods. It also expands quantum simulation capabilities by introducing longer-range interactions absent in atomic systems.
One immediate target is arranging the condensate in an optical lattice — an artificial crystal made of light — to simulate complex quantum materials. “The molecular BEC will introduce more flavor,” Will noted. Another direction involves exploring two-dimensional systems, where new physics is expected to emerge.
“It seems like a whole new world of possibilities is opening up,” Will said.
Why This Matters for Developers and Researchers
For developers working on quantum computing platforms, this breakthrough provides a clearer pathway to simulating real-world materials — particularly those with dipolar interactions common in magnets, superconductors, and exotic phases of matter. The ability to precisely control interaction strength opens new design spaces for quantum algorithms.
For condensed matter physicists, the molecular BEC offers a clean experimental platform to probe how quantum phases form under varying interaction strengths — helping explain phenomena like topological order and strongly correlated electron behavior.
“The work will have important impacts on a number of scientific fields,” said Ye. “Quantum chemistry, exploration of strongly correlated quantum materials — all stand to benefit.”
Research findings are published in Nature.
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