As understanding Bose-Einstein condensation is highly important to the study of magnetism and superconductivity, when scientists created the phenomenon back in 1995, everyone was understandably excited about the stage of matter. While current process of creating the Bose-Einstein condensates is time consuming and provides low energy output, researchers from MIT have invented a new technique to cool atoms into condensates in a faster way.
Previously, laser beams from different angles were trained at the cloud of atoms to limit atoms’ movements as these atoms moved close to the zombie-like state. As the atoms in the cloud collide with each other, the photons compress the clouds. After a certain point, the temperature inside the cloud starts to rise and at this point, lasers are turned off to allow atoms to cool down. However, more than 99 percent of the atoms go away from the cloud during the process.
In the new method, researchers used Raman cooling method to cool down the cloud of atoms to 1 microkelvin. During the process, the scientists used two laser beams to cool the atoms. The researchers used the first laser beam to create a light-induced magnetic field in the cloud. As the atoms’ energy is magnetized, it slows down the atoms in the cloud. As for the other laser beam, it was used to maintain the total energy of the cloud.
Talking about the latest findings, Vladan Vuletić, the Lester Wolfe Professor of Physics at MIT said, “Ultimately the photons take away the energy of the system in a two-step process. In one step, you remove kinetic energy, and in the second step, you remove the total energy and reduce the disorder, meaning you’ve cooled it”
“Before, when a photon came in, it was scattered by, say, 10 atoms before it came out, so it made 10 atoms jitter. If you tune the laser away from resonance, now the photon has a good chance of escaping before hitting any other atom. And it turns out by increasing the laser power, you can bring back the original cooling rate.”
Thanks to the latest method, the final result yielded over 70 percent of total atoms from the original number of atoms opposed to less than 1 percent retention rate using the previous method.