Quantum

Redefining Physics with Dr. Charles Brown narrated by Nia Burrell, JNIPER Fellow (2024)

Narrator: Whenever I tell people that I’m a physicist, they often respond with something along the lines of, “I absolutely hated learning physics in school!” or, “What do you even do as a physicist?” I think there’s a longstanding stereotype that physicists are these mysterious figures who spend all day writing crazy equations on chalkboards. Sure, maybe some physicists do spend their whole day at a chalkboard, but a lot of us actually do so many different and interesting things. My goal is to make physicists seem less mysterious, so I decided to talk to Dr. Charles Brown, a young Black professor at Yale University who started his faculty position in 2023.

Dr. Brown: My Name is Charles Brown. I’m currently an assistant professor of physics at Yale. I’m an experimental physicist who’s interested in really understanding the fundamental nature of the universe.

Narrator: Before we get into what it means to be an experimental physicist and a professor at Yale, I asked Dr. Brown to take me back to his days as a middle schooler and how he became interested in physics in the first place.

How Dr. Brown became interested in physics

Dr. Brown: I was a very science-interested kid that didn’t always have the resources to explore science the way that I really wanted to. But I had a lot of tenacity and a lot of encouragement from my mom to keep on exploring and keep on learning things.

Narrator: A lot of us might be able to relate to this–as kids, we might not always have the resources to explore science. But there are ways we can still gain a lot of meaningful knowledge. One of those ways that Dr. Brown did this was by going to his local public library where, in some cases, you can borrow up to 50 books at a time.

Dr. Brown: I was doing a lot of going to the library–I used to really love the library–and reading books about science. And then going to my garage and trying–and mostly failing–to do stuff that I had read about. I had become quite the tinkerer. I used to love to build stuff or take stuff apart. I had all of these experiments that I was doing.

Narrator: This “tinkering” and building and taking stuff apart–that’s a big part of what experimental physicists and engineers do. So, it makes sense that he became interested in studying these subjects in school as he grew up.

Dr. Brown: Because I spent so much time building things, I developed a lot of intuition for aspects of engineering. So because of that, I ended up majoring in engineering in college. I was really interested in physics, but I do think for a long time that “physicist” was something you could really do. I’m not sure if that makes any sense, but I felt that way as a kid.

Narrator: It makes a lot of sense. Like I said in the beginning, people always ask me what I do as a physicist because, as kids, we don’t learn a lot about what goes on in a modern physics lab. So let me explain. Experimental physicists and engineers do have some overlap. On one hand, engineers design and build things. They like to focus on creating solutions to different problems that we have in the world like with technology, infrastructure, or the environment. On the other hand, as experimental physicists, we can do a lot of designing and building too. But our interests are more about the science behind why things work and how we can understand the universe better. Dr. Brown eventually realized that he wanted to know more about how things work, so he eventually switched from studying engineering to physics in college. He received his Bachelor’s degree in physics in 2013 from The University of Minnesota, Twin Cities.

Path from college to becoming a professor

Dr. Brown: My path in college was quite windy. I was a good wrestler in high school, so I was recruited to wrestle in college. I had finished high school a little bit early. I did that for a couple of years; my wrestling career was sort of forcibly ended. And then, I said okay, time to buckle down and just focus on academics. I ended up moving to Minnesota after having gone to a couple of community colleges because I needed to take some classes and have the right prerequisites to transfer into the physics major at the University of Minnesota. And that whole process took my six years actually, so it was quite windy.

Narrator: After college, Dr. Brown went on to study more physics in grad school, which is where he earned his Dr. title from Yale University in 2019.

Dr. Brown: I went to do a Ph.D. in physics at Yale, and I did a bunch of really awesome science. I was fortunate to have a great Ph.D. advisor. He’s like a football coach that’s really good at getting you huddled up and getting you excited to get a draw on the next play. Every time I had a one-on-one with him, I’d leave feeling like, “Oh my god, this is super important work. I’m so excited to be able to do this!” So I always left feeling very energized.

Dr. Brown: Grad school was very transformative for me in a number of ways. I learned that I could build an experiment and use it to do interesting science. It also meant learning about a lot of physics that was initially unfamiliar. I was just deeply fascinated by the science, so I really dug my heels in. And that was the process of realizing, “Oh wow, I guess I do have some skills that I’ve developed. I guess I really can be effective and do some new stuff and lead the way,” at least from the student standpoint to make some new science happen.

Narrator: This is very true that for a lot of scientists, grad school is a really big learning experience that makes you realize that you can do so much more than you thought you were capable of. After grad school, Dr. Brown went on to do a postdoc in 2019 at the University of California, Berkeley. A postdoc is a research position that people often do between grad school and becoming a professor.

Dr. Brown: I ended up doing a postdoc at Berkely and also had a great experience there. It was definitely complicated by the pandemic. And certainly, as a postdoc who is looking to do science, it was a little painful to have the lab shut down for four months. It gave me a lot of time to read. I realize that is a very fortunate thing to do in what was a very difficult time for a lot of people, so that fact is not lost on me. I switched research fields quite a bit going from Ph.D. to postdoc. I was there for a few years. I learned some awesome science and experimental techniques from an awesome postdoc advisor.

Narrator: Even after earning a Ph.D., there’s still so much more to knowledge to gain. A big part of being a scientist is constantly learning new things.

Dr. Brown: Now, I’m a faculty member at Yale, and I’m using a lot of what I learned as a postdoc–and actually as a Ph.D. student too–to do what I hope are some really exciting experiments in my own lab.

What does a physicist do?

Narrator: Now let’s fully answer the question, “What does a physicist even do?” I asked Dr. Brown to give us a breakdown of what his research is about.

Dr. Brown: I’ve gotten really interested in the physics of crystals. What is a crystal? It’s an arrangement of atoms that have perfect spacing between each atom.

Narrator: So, crystals, like diamonds, for example, are all made up of a grid of atoms. And every atom has at least one electron. Electrons are charged particles, which is why they produce electricity in a light bulb, for example.

Dr. Brown: These electrons hop around all the atoms that make up the crystal, and the details of how those electrons hop around determine lots of properties of the crystal. It determines how the crystal conducts electricity, how the crystal conducts heat, what color the crystal is, whether the crystal is transparent or not, whether the crystal is magnetic. There are so many properties that are actually determined by the details of how electrons move in crystals. That is inherently a quantum process.

Dr. Brown: If we’re talking about quantum physics, what does that mean? Quantum physics refers to the physics of very very very small sizes–very very small lengths. At those very small lengths or small sizes, some of what we know from what we experience on a day to day falls away. There’s new intuition that you have to build, and that’s because objects start to behave more like waves. The wave nature of all these objects imbues them with interesting new properties.

Narrator: Dr. Brown and a lot of physicists are interested in quantum physics. Quantum is the study of the wave behavior of small objects. When we say waves, think about the waves you know, like the waves in an ocean or the waves in a slinky. Really small particles can behave similarly. Okay, now that we know what quantum physics is, let’s learn more about how it relates to crystals.

Dr. Brown: I build synthetic crystals. So instead of having real solids with real atoms that have this perfect spacing, I make grids out of laser light. I shine a whole bunch of lasers together, and they make a grid that looks like the underlying structure of a bunch of atoms in a solid. And I put really cold atoms into my grid made of light. The analogy is: my grid of light is like in a solid an underlying perfectly spaced arrangement of atoms, and my atoms are like the electrons that hop around in the solid.

Narrator: Okay, let’s recap because this isn’t something we hear about every day. Dr. Brown has described that a real crystal is made up of a grid of atoms with electrons hopping around. Similarly, a synthetic crystal is made up of a grid of lasers with cold atoms hopping around. You can think of a synthetic crystal as a bigger version of a real crystal.

Narrator: Another key difference between real and synthetic is that electrons hop around quickly, while ultracold atoms hop around slowly in comparison. But in both scenarios, the “hopping” is where the quantum physics happens.

Dr. Brown: I study the details of how really cold atoms hop around grids of light. I like this system because it’s a lot bigger actually than the system of electrons moving around real solids. And so that means that all of the interesting quantum physics processes that you want to be able to study–they happen more slowly. We can take direct images much more easily of atoms as opposed to electron dynamics. It’s just the nature of modern atomic physics–this is what I do now–we have really awesome control of our experiments. There are really unique experiments we can do that are sometimes much harder to do if you’re studying real solids.

Narrator: To summarize, Dr. Brown is building synthetic crystals so that we can understand the quantum, wave-like properties of small objects. These physical properties are new, exciting, and really different from what previous physicists like Isaac Newton have taught us in the past.

Narrator: As a physicist, Dr. Brown gets to do a lot of exciting things. He builds experiments with lasers and atoms, does 3D modeling, writes code, and even manipulates equations (perhaps even on a chalkboard!). And we can’t forget that on top of doing all of these things, he’s also a professor who works with students.

Dr. Brown: A very important part of my job is mentoring and teaching. I really enjoy the experience of working with other scientists in the lab, especially younger scientists I have the opportunity to teach as we’re working towards doing science. I like that it’s a dynamic job that requires a lot of moving parts to work, and lots of the different parts of my job speak to my different interests as a person. And it gives me a way to study physics but also have some impact in society. I can train younger people to go and do science and I can be a role model.

Being Black in Physics

Narrator: Dr. Brown has told us a lot about his journey to becoming a physicist and what his research is all about. The last thing I wanted to know was what he would say to young minorities who are interested in science.

Dr. Brown: Certainly, as I look around, there are very few Black scientists in science, let alone in physics. This happens for a number of reasons–a lot of them are societal. It’s an unfortunate case that depending on where you live in this country, your schools might be drastically differently funded. So maybe you have a large and robust STEM program where you get to do lots of science and build robots. Maybe you’ve been drawn a different hand in leg ups in your early life, and that’s okay. That is not about you as a young student. That's about societal issues that have the effect of cubby holing you into certain tracks. And so, you should not be confused about having a track defined for you and what you can achieve and actually accomplish. These are not the same things.

Narrator: This is 100% true. You can be a great scientist no matter what your race, gender identity, or economic background is.

Dr. Brown: It’s understandable to feel oh like there’s not many Black people in science, so maybe science is not for me. I get it. But Black people have been doing science for a very long time, and there are many important black scientists. It turns out that a really important experimentalist that helped usher in this first quantum revolution that changed how we see the universe was a Black man, and that is Elmer Imes.

Narrator: Elmer Imes was the second Black man to earn his Ph.D. in physics in the United States, and he was pretty brilliant. He completed his doctorate in the year 1918, and he studied the quantum behavior of molecules. [Source]

Dr. Brown: He was the person to verify that this is indeed the right way to think of molecular physics at the quantum level. And this was back in the early 1900s, and I think very very few people know about him. And this is but one example. There are many examples of black people in other science fields doing this. There are many examples of women in physics really offering new insight that just changes how we understand the universe and how deeply we understand it. So, know that there are examples of people like you or nearly like you that have not only done science but really have done it at the highest level that has completely transformed our knowledge of the universe and there’s no inherent reason why that can’t also be you. I would say if you’re interested in science and STEM, you should absolutely explore it.