This podcast tells the story of the scientific pursuit of absolute zero, the lowest theoretically possible temperature, and the groundbreaking discovery of the Bose-Einstein condensate.

Reaching absolute zero, where atoms and molecules have the lowest possible kinetic energy, is impossible in a laboratory setting, but scientists have managed to cool atoms down to a tiny fraction of a degree above it. The podcast discusses some of the historical milestones in this pursuit, starting in the 19th century with Scottish physicist and chemist James Dewar.

Dewar developed new techniques and tools for working with very cold fluids and gases, including the vacuum flask that is still widely used today. Dewar was also driven to liquefy hydrogen. This procedure, however, was complicated and risky. Scientists at the time had to liquefy gases one after another to create colder and colder environments. This involved high pressure and extremely low temperatures, which led to several accidents in Dewar's lab.

Though Dewar successfully liquefied hydrogen in 1898, he was unable to liquefy helium, which has an even lower temperature threshold. It was Dutch scientist Heike Kamerlingh Onnes who was the first to liquefy helium in 1908. These breakthroughs in reaching ultra-low temperatures paved the way for the discovery of new states of matter. In the early 20th century, scientists started to study the unique properties of super-cooled matter. They discovered superconductivity, a state in which certain substances lose their electrical resistance, and superfluidity, a state in which liquid helium loses its viscosity.

Building upon these discoveries, in 1925, scientist Satyendra Nat Bose developed a new mathematical model that was later used by Albert Einstein to predict the existence of the Bose-Einstein condensate (BEC), a new state of matter where atoms lose their individual identities and become indistinguishable from one another.

Reaching the temperatures needed to create a BEC, however, required new technologies. Scientists achieved this using laser cooling and magnetic trap methods, which allowed them to cool atoms down to a few millionths of a degree above absolute zero. Finally, in 1995, researchers successfully created a BEC in the lab for the first time, marking a groundbreaking achievement in the field of physics and our understanding of matter.

(The dialogue was created using the NotebookLM tool.)

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