In the mid-1920s, two absolute giants of the world of physics, Satyendra Nath Bose and Albert Einstein, theorized the existence of a strange quantum state of matter that would eventually be named in their honor: the Bose-Einstein condensate ( BEC). The luminaries of the 20th century thought that if particles were cooled to ultracold temperatures—mere fractions of a degree from absolute zero (-459.67°F)—and kept at low densities, they would form an indistinguishable whole.
Some 70 years later, scientists at the University of Colorado at Boulder proved Einstein and Bose right. Since then, BECs have been a vital tool for exploring the quantum properties of atoms, and a series of advances – whether cooling the particles further or getting them to form diatomic molecules – have made them increasingly useful in the search for the underlying physics that governs the universe.
Now, physicists at Columbia University – in collaboration with Radboud University in the Netherlands – have taken the next step in this century-long journey through the BEC by creating a sodium-cesium condensate just five nanoKelvin above zero. absolute. Although this is an impressively cold temperature, the most important thing about this impressive work of experimental physics is that the resulting BEC is dipolar, meaning it has a positive and negative charge. The team used a previously revised technique that uses microwaves to cross “the BEC threshold,” according to a press release. The results of this study were published this week in the journal Nature.
“By controlling these dipole interactions, we hope to create new quantum states and phases of matter,” Ian Stevenson, a Columbia postdoc and co-author of the study, said in a press release.
Microwaves are often associated with heating, but Tijs Karman, a collaborator on the study at Radboud University, suggested that microwaves may act as shields, essentially protecting molecules from lossy collisions, while hot molecules melt away. removed from a sample, which has an overall cooling effect. The team tested the microwave technique in 2023, but this new study added a second microwave field that was more effective in creating the desired BEC.
“We really have a good idea of the interactions in this system, which is also critical for next steps, such as exploring many-body dipole physics,” Karman, who was also a co-author of the study, said in a press release. “We have devised schemes to control the interactions, tested them in theory, and implemented them in experiment. It has truly been an amazing experience to see these ideas for microwave ‘shielding’ come to life in the laboratory.”
The creation of this dipolar BEC opens the door to the creation of many other forms of exotic matter, such as “exotic dipolar droplets, self-organizing crystalline phases, and spin dipolar liquids in optical lattices,” according to the paper. But these are just a few of the dozens of possible applications that this new BEC could help make a reality. Since this experiment allows for precise control of quantum interactions, according to Jun Ye, an ultracold scientist at UC-Boulder, the implications for quantum chemistry could also be very profound.
The little-known fifth state of matter in the universe continues to surprise us more than a century after its surprising introduction into the known world of physics.
Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff from him at Gizmodo and Paste if you look hard enough.
