A new type of Bose-Einstein condensate (BEC) has been created in the laboratory of physicist Sebastian Will at Columbia University, paving the way for novel research in quantum physics. Discover how this achievement, the result of decades of work, could transform our understanding of quantum phenomena.
Sebastian Will’s laboratory, in collaboration with Tijs Karman of Radboud University in the Netherlands, has succeeded in creating a unique quantum state of matter, a Bose-Einstein condensate (BEC), from molecules. This BEC, cooled to just five nanoKelvin, or about -459.66°F, is composed of sodium-cesium molecules. These polar molecules, carrying both a positive and a negative charge, facilitate long-range interactions, paving the way for fascinating physical phenomena.
Future research in the Will lab with these molecular BECs includes exploring new types of superfluidity, a state of matter that flows without friction. They also hope to use these BECs as simulators to recreate the quantum properties of more complex materials, such as solid crystals.
A History of BEC Science
The science of BECs dates back a century to physicists Satyendra Nath Bose and Albert Einstein. In a series of papers published in 1924 and 1925, they predicted that a group of particles cooled almost to a standstill would condense into a single larger entity, sharing properties and behaviors dictated by the laws of quantum mechanics . The first atomic BECs were created in 1995, an achievement rewarded with the Nobel Prize in Physics in 2001.
Since then, laboratories have steadily created atomic BECs from several types of atoms, expanding our understanding of concepts such as the wave nature of matter and superfluids. However, atoms are relatively simple and generally do not exhibit the complex interactions that can arise from polarity. Scientists therefore sought to create more complex versions from molecules.
The role of microwaves in cooling
To achieve even lower temperatures, Will’s team used microwaves. These electromagnetic waves can create small shields around each molecule, preventing collisions and allowing the hottest molecules to be preferentially removed from the sample. By adding a second microwave field, the cooling became even more efficient, allowing the sodium-cesium to cross the BEC threshold.
In addition to reducing collisions, the second microwave field can also manipulate the orientation of molecules, providing a way to control their interactions. “By controlling these dipolar interactions, we hope to create new quantum states and phases of matter“, said Ian Stevenson, postdoctoral researcher at Columbia.
A new horizon for quantum physics
The results obtained by the Columbia team will have important impacts on several scientific fields, including the study of quantum chemistry and the exploration of highly correlated quantum materials. “Will’s experiment features precise control of molecular interactions to steer the system toward a desired outcome, a marvelous achievement in quantum control technologycommented Jun Ye, a pioneer in ultracold science based in Boulder.
With molecular BECs stable for about two seconds, the Columbia team can now test many theoretical predictions. One idea is to create artificial crystals with BECs trapped in an optical array made of lasers, enabling powerful quantum simulations that mimic interactions in natural crystals. “Molecular BEC will introduce more complexity”Will added.
Researchers also want to use BECs in a 2D system. “When you go from three dimensions to two, you can always expect new physicssaid Weijun Yuan, doctoral student and co-first author. 2D materials are a major area of research at Columbia, and a model system composed of molecular BECs could help explore quantum phenomena such as superconductivity and superfluidity.
In conclusion, the creation of this molecular BEC opens a new world of possibilities for quantum physics research, offering unprecedented perspectives for understanding and manipulating quantum interactions at a fundamental level.
Illustration caption: Using microwaves, Columbia physicists have created a Bose-Einstein condensate, a unique state of matter, from sodium-cesium molecules. Credit: Will Lab, Columbia University/Myles Marshall
Article: “Observation of Bose-Einstein Condensation of Dipolar Molecules” – DOI: 10.1038/s41586-024-07492-z
