Looking for a Dinosaur in the Electron

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Sigma Pi Sigma Physics Congress (PhysCon)

November 3, 2016 to November 5, 2016

San Francisco, CA

Meeting host:

Sigma Pi Sigma


Adam Campbell, Annelise Ettema, Caroline Fedele, and Daniel Seiter

SPS Chapter:

Grove City College students with Nobel Laureate Eric Cornell (center).

By noon on Saturday, few attendees of the Society of Physics Students Quadrennial Congress expected that the best was yet to come. Many were reluctantly realizing that they would be boarding flights in a few short hours, leaving the incredible experience of the congress behind. Yet our focus was on the intimidating interview we would conduct at 2:15pm. We sought to calm our nerves and review our notes one last time, as we were assigned to interview Eric Cornell. Renowned for his work as the first scientist to synthesize the Bose-Einstein condensate, Cornell has published over 100 scientific papers and holds honors from many prestigious institutions. In short, a conversation with Eric Cornell is no ordinary or casual conversation for four undergraduates.

“I think the worst part was worrying about my questions,” junior physics major Daniel Seiter recalled “What if I sound like an idiot? He’s a Nobel laureate!”

Cornell entered the interview room with a smile and a cup of coffee. Right away, the tension in the room evaporated. Simply put, Eric Cornell is one of the most uniquely gifted and approachable physicists imaginable. His fun-loving personality, quick humor, and brilliant mind make him an incredible resource for undergraduates.

“I love meeting with undergrads,” Cornell announced. “Their energy and carefree attitudes [because they don’t have to earn a living yet] are great!”

Grove City College student reporters and Zone 11 AZC Lisa McDonald interview Eric Cornell prior to his talk.

When asked what advice he would offer to undergraduates, Cornell emphasized the importance of writing and communication in modern science. He asserts, “Projects are too hard alone! Modern scientific process is done in groups of people. No matter the field, writing is valuable for many different reasons—explaining what you're doing, applying for grants, and writing lectures.” In his research program at University of Colorado at Boulder, Cornell considers unleashing students on projects while providing minimal guidance to be the best approach. He chuckles, “Students get nervous when I get close to their projects. It’s a better experience if they think of it as their own—that way when it stops working, it’s their fault.”

Regarding the future of physics, Cornell calls for massive collaboration efforts between physicists and other sciences, as they are all interrelated and depend on each other. “Being successful in physics is asking good questions and going out and answering questions that aren't necessarily physics.”

Eric Cornell’splenary talk reflected many of the same ideas as his interview. His main piece of advice was to stay broad. Do not get boxed into one discipline. As physicists, we believe our research is what is most important and will continue to be the most important for the foreseeable future. However, Cornell wisely forewarned the audience that those whostudy “exactly this effect in this material and nothing else matters” end up being stuck in a canyon. As a physicist, you will probably—definitely—not be studying the same thing in ten, even five years. He strongly recommended going out and learning something new; find a new interest, a new passion, and stay curious, striving for a broader, more rounded education.

In fact, Dr. Cornell’s current research has nothing to do with his Nobel-Prize-winning research on the Bose-Einstein condensate, he said. He is working in a completely new and fascinating direction: trying to discover the electron electric dipole moment (EDM).

In order to understand this phenomenon, he went back, way back, to the very beginning: the Big Bang. In the momentafter the Big Bang, there was a “mass cosmic wedding” of particles. Each one found its soulmate. Protons married anti-protons; electrons, anti-electrons; and neutrons, anti-neutrons. Matter came together with a rather violent pop—BOOM! However, due to a slight asymmetry in matter and anti-matter, there was stuff left over. “Who are these final, few, lonely particles that no one wanted? Yeah, they’re you.” So if most of the matter in the universe was obliterated in this violent way, how can he study it? The same way scientists study dinosaurs, by using their bones. We can’t see the dinosaurs anymore, but we can figure out what they looked like and how they lived by what they left behind. This is why Cornell studies the EDM: to figure out what happened in the momentsafter the Big Bang, and study the very dawn of time based on these “fossils” existing within the electron. But what does the EDM have to do with the fact that there were “a tiny bit more electrons than anti-electrons 14 billion years ago?”

Cornell’s research is trying to explain why there are asymmetries in nature; the theories of why we are here. The electron happens to be perfect—it spins and has magnetic north and south poles. Are the north and south poles the same, though? If it can be proved that the electron has different magnetic poles, then there is evidence for the electron EDM. The EDM is proof that the center of mass of an electron and the center of charge are not in the same location. The problem, however, is that no one has been able to measure the EDM thus far.

To measure the EDM, Cornell is using molecular ions. To put the accuracy of this experiment in perspective, Cornell gives us this example: if the electron were the size of the earth, the extra thickness of charge on the north pole would be about the thickness of a virus. Thus, Cornell gave the number one rule of experimental physics: “If you want to measure something very carefully, change it into a frequency and measure that!” The problem with throwing an electron into a strong electric field is that it will fly off. To get by this, Cornell uses hafnium fluoride in an ion trap, because the elemental bond creates an incredibly strong electric field. This technique of using molecular electric fields allows Cornell to generate potentially highly accurate results.

Cornell “blinds the data” in his experiment. This means that before the researchers read their measurements, the computer adds on a random number that they do not know. Cornell asserts, “Finding the EDM is a big deal. Whether the electron has an EDM or not is a big deal in physics and we care about it so much we may think we know what the answer ought to be.” By blinding the data, he removes the temptation to make the data fit expectations. In several weeks, Cornell will “unblind” the data to publish their results. He also has hopes to move to a better molecule, thorium fluoride, for more accurate readings.