Written by Tyler Wilson.
Dr. Ethan Elliott, who graduated St. Mary’s College of Maryland (SMCM) in 2006, received an award from NASA in October 2019 for his work in NASA’s cold atom lab and being part of the team that generated, according to insideSMCM, “the first Bose-Einstein Condensate in Earth orbit.” The creation of the Bose-Einstein Condensate (BEC) in a dilute atomic gas, something even Einstein did not think would be possible, is not only a triumph of the human mind, but is a product of the 21st century technologies that scientists now have at their disposal.
In introductory physics, students are taught about the three main states of matter: liquid, solid and gas. While these states of matter each have their own unique properties, the atoms that make up each of these states of matter will collide and then go their separate ways if they run into each other. The atoms are showing particle behavior by bouncing off each other, which is how atoms normally behave. According to Elliott, atomic BECs are “massive, neutral atoms cooled so close to absolute zero that they become a collection of large matter waves.” If an atom is cooled to an extreme degree, like a BEC is, then they exhibit a more “wavelike behavior,” meaning that instead of bouncing off each other, they are capable of “passing through each other.” This is because cooling particles lowers their momentum, which in turn increases their wavelike behavior. Naturally low momentum occurs for particles with low mass, such as electrons, but through Elliott and his team’s work, they were able to “very unnaturally” manipulate atoms, which are “many thousands times more massive than electrons,” into exhibiting that wavelike behavior.
In order to actually generate the BEC, Elliott and his team created a lab in the International Space Station that turned on when all the astronauts were asleep. This is because “the most advanced cooling techniques are improved by microgravity” so that a free falling BEC exists for longer periods of time in space. Setting up the space lab was a long and arduous process that required patience and ruggedizing advanced technology. It functions by releasing rubidium and potassium atoms into a vacuum chamber that are precooled with lasers and loaded into a magnetic trap where the atoms evaporate to a billionth of a degree above absolute zero. A final laser pulse casts a shadow of the BEC on an onboard camera and sends a picture back to NASA’s Jet Propulsion Laboratory. This entire process would not have been possible without decades of advances in modern experimental physics, which is an amazing set of tools to deploy in space.
The discovery of BECs has many fascinating applications. First of all, as Elliott explains, “everything around us is made of atoms,” so we can study these atoms “for their intrinsic properties and fundamental science.” Besides learning about fundamental science, ultracold atoms can be used to model systems that we don’t have access to, such as the “interior of a neutron star” or the “the quark gluon plasma of the big bang.”Lastly, since the BECs have mass, they can be “extremely sensitive probes of inertial forces: rotations, accelerations, or gravity” which is needed because as Elliott says, understanding gravitational effects can offer insights into many poorly understood areas of physics such as the nature of “dark matter” or “dark energy.”
Elliott said his education at SMCM is “directly responsible for preparing [him] to do this work.” He worked at the PAX River Naval Air Station with SMCM physics professor Dr. Charles Adler, and there he “first started working with ultracold atoms,” where the Navy was interested in using “the inertial sensing properties of ultracold atoms to create a new generation of gyroscopes for dead reckoning navigation in GPS denied environments.” Elliott claims that summer research experience, such as he received at SMCM, is “the single biggest determiner in graduate school admission when applying to a PhD program in a scientific field.”