When Higgs Fly

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Category: Department News

Published: Thursday, January 26 2023 00:01

When Christopher Palmer was a physics graduate student at UC San Diego, he had to decide whether to specialize in supersymmetry or search for the Higgs boson.

Though there was no experimental evidence of the Higgs boson’s existence at the time, Palmer was convinced that this elusive elementary particle—believed to be linked to a field that gave mass to everything in the universe—was somewhere out there.Chris Palmer

“The Higgs boson is such a cornerstone of a very well-established theory called electroweak theory,” Palmer said. “It could be a lack of imagination on my part, but I could not imagine the Higgs boson not existing.”

He trusted his gut and dedicated his studies to the Higgs, which set him on course to Switzerland to join one of the experiments at the Large Hadron Collider (LHC) beginning in 2010. Luck was on his side, and he ended up being part of the research group that recorded the highest number of Higgs bosons in their analyses, contributing to the particle’s official discovery the following year.

He hasn’t looked back since. In March 2021, Palmer became an assistant professor of physics at the University of Maryland, where he continues to study the Higgs in search of the next big discovery.

‘Deeply weird’ physics

Palmer’s first academic love wasn’t actually physics—it was math.

“I loved math in high school, so I thought, ‘Yeah, I’ll do math in college,’ but that was sort of my ‘hobby major’—and I’m glad it was because I ended up not enjoying mathematical proofs that much,” he said with a laugh.

A fascination with what existed “beyond Earth” prompted Palmer to declare a second major in astronomy as an undergraduate student at USC. But it wasn’t until he took an upper-level course in quantum mechanics—and became enamored with its mathematical intricacies—that he developed a deeper appreciation for physics. 

“It was a new way to use many different aspects of math,” Palmer said. “There’s linear algebra and complex numbers. Taking these integrals and mixing all that up in a pot was really fun for me. But there was also some new physics that was deeply weird, and I couldn’t get enough of it.”

Palmer needed only one quantum mechanics course to meet the requirements of an astronomy major but enjoyed it so much that he took two. After graduating with a bachelor’s degree in mathematics and astronomy in 2007, he took a short drive south to UC San Diego to continue his studies—this time as a Ph.D. student in physics.

Right place, right time

Once Palmer decided to search for the Higgs boson, he joined the Compact Muon Solenoid (CMS) experiment at the LHC. Palmer teamed up with a group that was looking for evidence of the Higgs boson’s decay into two photons during proton-proton collisions.

This turned out to be a serendipitous assignment. His group ultimately saw an enormous excess of Higgs bosons in their analysis. 

“At the time in 2011, no one else at CMS had actually seen much of anything in their data, and in my analysis there was the biggest excess of Higgs boson particles in any of CMS’ searches,” Palmer said. “The discovery was literally happening at my fingertips.”

Palmer was so focused on the work that he didn’t have time to get excited about the actual discovery of the Higgs boson, which was confirmed and publicized in 2012.

“There was a whole lot of double- and triple-checking everything in early 2012. I wasn’t sleeping all that much,” he said. “I got excited afterward.” 

With one major discovery under his belt, Palmer was hooked on Higgs. After earning his Ph.D. in 2014, he became a postdoctoral researcher at Princeton University, where he participated in luminosity experiments and studied the Higgs boson’s decay to bottom quarks—the “most elusive decay” anyone had observed up to that point. 

In 2021, Palmer joined UMD with plans to study signatures of the Higgs boson in greater detail and depth, while also having the flexibility to explore other research interests down the line. 

“One of the things that I really love about this department is that there are so many different types of research that are represented by the faculty,” Palmer said. “In 10 years, if I want to do something different, I don’t know any place where it would be easier.”

Continent-spanning research

Palmer continues to participate in LHC experiments, and much of his work can be done without ever leaving campus. He is part of a team that is studying a new CMS detector, called the MIP Timing Detector, that will more precisely measure charged particles. Because the CMS experiment will need to be operational at -30 degrees Celsius, Palmer and his team are building a cold box at UMD to test components of the detector under extreme conditions.

This research is funded by a Department of Energy grant, which also supports the work of Physics Professor Sarah Eno and Associate Professor Alberto Belloni. Though all three faculty members are involved in LHC experiments, Palmer said they each have their own interests and areas of expertise, which keeps things interesting.

“It’s nice to see what other people are doing, and you don’t always get that when you work in a group that has all the same physics interests,” Palmer said. “It’s also good for the students because they really get to see what is going on in vastly different corners of the experiment, which is important in a giant experiment like CMS that has 3,000-some people in it.” 

In addition to his research, Palmer works to make physics a more inclusive field and is currently exploring ways to improve student mentorship and support for students from historically underrepresented groups. He serves on the executive committee of the American Physical Society’s Forum on Diversity & Inclusion, as well as the College of Computer, Mathematical, and Natural Sciences’ Diversity & Inclusion Advisory Council. He is also the director of Pathway to Physics PhD (P3), a UMD fellowship program that offers fully funded physics degrees, with priority given to applicants from historically Black colleges and universities and minority-serving institutions.

Eye on the collider

When he’s not busy with campus initiatives or teaching classes, Palmer keeps tabs on the data flowing out of the LHC. A monitor next to his office door displays numbers and charts showing the latest data from LHC experiments, including the luminosity measurements that Palmer specializes in. 

“Most of the time I’m engaged in my classes and meetings and other things that I’m immediately involved with,” Palmer said, “but I’m always keeping an eye on what’s going on at the LHC out of the corner of my eye.”

Palmer’s research—and a touch of luck—brought him face-to-face with some of the biggest discoveries in physics. When the next uncharted phenomenon shows up in an experiment, Palmer doesn’t want to miss it.

Written by Emily Nunez

Taking the SMART Path

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Category: Department News

Published: Thursday, January 26 2023 00:01

In 2021, when Isabelle Brooks left her home in Minnesota to study physics at the University of Maryland, she knew it would mean a big transition—from an all-girls high school with fewer than 500 students to a huge college campus with more than 40,000 students. It turned out to be even more exciting than she expected.

“It was definitely a culture shock,” Brooks recalled. “I told my roommate it was crazy to me that I kept seeing so many faces I didn’t recognize. I was around so many different people doing so many differIsabelle Brooksent things—it was a really cool and exciting experience.”

Brooks’ experiences have exceeded her expectations in more ways than one, and although she’s only a sophomore she’s already charting her path toward a career in physics. One big boost in that direction came last year when she was awarded a Department of Defense SMART (Science, Mathematics, and Research for Transformation) Scholarship. 

SMART Scholars receive full tuition for up to five years and hands-on internship experience working directly with an experienced mentor at one of over 200 innovative laboratories across the Army, Navy, Air Force and Department of Defense, plus a stipend and full-time employment with the Department of Defense after graduation. 

This summer, Brooks will intern at a U.S. Army facility in Maryland. 

“I’ll be working at Aberdeen Proving Ground with the Department of Defense,” Brooks said. “The lab I’ll be working with focuses on satellite communications and other innovative technologies for our armed forces. It’s super exciting.”

Physics in the family

Always a strong student, Brooks got an early introduction to physics thanks to her father who studied physics when he was in college.

“My dad was my biggest influence,” she explained. “He’s a patent attorney now and he works with a lot of science and technology, which has been super cool to watch as I’ve been growing up.”

Despite her interest in her dad’s work, Brooks wasn’t initially drawn to physics herself.

“My dad was always like, ‘It’s really important to study science,’ but I didn’t really want to,” Brooks recalled. “My freshman year in high school I actually did not do well in my introductory physics class at all, I didn’t like the content and I told my dad, ‘I’m never doing this.’”

All it took was one class to change her mind.

“In my senior year I ended up taking honors physics and I had the best, most supportive most influential professor who helped me understand that I am really good at this and there is an opportunity for me to do much more with it,” she said. “After that, it really made sense to me—I liked seeing how physics is playing out in the real world, and I knew this was something I wanted to do.”

So many possibilities

In the summer after Brooks’ first year at UMD, one of her relatives who works with the Defense Department encouraged her to apply for the SMART Scholarship to help her achieve her dream of a degree in physics. Months later she got the news she was hoping for.

“I was checking my inbox every day and when I saw the email I was shaking because I knew this had to be it,” she recalled. “When I opened the email and got the good news that I’d received the scholarship I just felt so honored. There are just so many possibilities that can come from this.”

Since then, regular check-in meetings with her SMART mentor James Mink, Chief of the Tactical Systems Branch (SATCOM) have helped Brooks learn more about the opportunities ahead and prepare for her summer internships. This summer—and every summer until she graduates—she’ll work directly with her mentor at the U.S. Army DEVCOM C5ISR Center - Aberdeen Proving Ground, gaining valuable hands-on experience and training that will prepare her for a full-time position there after graduation.

Brooks credits her participation in the FIRE (First-Year Innovation and Research Experience) program and her work with the Simulating Particle Detection research group for helping her build a strong foundation for her research, which has also focused on the challenges of quantum Fourier transforms—mathematical models that help to transform the signals between two different domains. 

She’s gained more confidence in herself and her abilities every step of the way.

“My parents always raised me to believe I could do anything I put my mind to, overcome any obstacle, but I think coming to such a big school, at first I wasn’t sure if I could really do this,” she recalled. “But now I just feel like I’ve opened up so much more confidence in myself and an awareness of my ability and my strength as a student, and that feels really good.”

Brooks continues to explore her fascination with physics in exciting and unexpected ways, thanks to professors who challenge and inspire her. Her favorite class this year was PHYS 235: The Making of the Atomic Bomb.

“It’s taught by Professor Sylvester Gates, who I think is the coolest person ever,” Brooks said. “I was so excited when I was in that class, but it was definitely hard. If I wasn’t a physics major, I think I’d be crying with the problem sets we had and the material we worked on, but that class and a lot of my physics classes have pushed me to think in new ways.”

It's been less than two years since Brooks came to UMD from a small Minnesota high school, but now as she pursues her passion for physics and looks ahead to the opportunities that will come with her SMART Scholarship, she’s thinking big.

“I just have this feeling that I can do a lot more with my life and my education than I ever grasped,” she explained. “I think with this Defense Department scholarship I’ll most likely pivot towards applied research and satellite communication technology, and knowing that the work I’ll be doing will actually support people who fight for our country is incredibly amazing. I can’t wait to make a difference.”

Written by Leslie Miller

Alum Jonathan Hoffman Heads Toward New Horizon in Navigation Science

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Category: Department News

Published: Thursday, January 26 2023 00:01

As a PhD graduation present, UMD physics alumnus Jonathan Hoffman’s adviser gave him a signed copy of the book Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time. The book follows John Harrison, an 18th-century carpenter who took it upon himself to solve what was known as the longitude problem.

Jonathan Hoffman Back then, ships at sea had no way of measuring their longitude—their position east or west of the prime meridian—causing many to get lost and often shipwrecked as a result. Harrison built five generations of clocks—which he named H1 through H5—culminating in the most precise clock of his time that sailors could use to precisely track the sun’s location at noon and thus infer their longitude.

Longitude quickly became Hoffman’s favorite book. Eight years later, as a program manager at the Defense Advanced Research Projects Agency (DARPA), Hoffman started a new program called H6 seeking to build a ‘spiritual successor’ to Harrison’s clocks: a “6th clock” that would be a compact, affordable, and precise device that would help navigate in situations where a GPS signal is unavailable. “It's the clock that Harrison would build to solve today's timing problem,” Hoffman says. 

Harrison’s story was mired in controversy. In 1714, the British Parliament announced the Longitude Prize, an award of up to 20,000 pounds for anyone who could solve the longitude problem, but it was overseen by the royal astronomer—a proponent of the mainstream star-gazing (rather than Harrison’s timekeeping) approach. Although Harrison was awarded various prizes throughout his 45 years of work, he was never officially awarded the full prize.

As a program manager at DARPA, Hoffman’s role parallels not that of Harrison, but that of the Board of Longitude, which was established to oversee the prize. But his H6 program also seeks to avoid the mistakes made by that board. Instead of looking for a solution from a particular well-established technology, Hoffman wants to give scientists the opportunity to bring in new outside-the-box ideas. “I wanted to question if there’s a different way, a way of going back to the drawing board and making clocks, something that could be incredibly small but still maintain time correct to a microsecond for up to a week,” Hoffman says.

Scientific Roots

Hoffman hadn’t always had an eye toward project management. Like most who pursue a physics PhD, he grew up interested in science, broadly defined. “I always would like to grab books and look at astronomy pictures,” Hoffman recalls. Through high school and college, his interests in science, and physics in particular, deepened further. “I think it's fascinating that there's an underlying connection and description and law for how things function,” he says.

Entering graduate school at UMD in 2009, Hoffman intended to study string theory. “I was really enamored with the idea of understanding how all of the forces were unified,” he recalls. But a conversation with a theoretical physics professor at UMD steered Hoffman towards a more practical path in experimental physics. 

With an eye towards the future, Hoffman joined a lab overseen by Professors Luis Orozco and Steve Rolston, in collaboration with Fredrick Wellstood and Chris Lobb, working on a novel idea to combine different quantum computing technologies for the best of both worlds. The idea involved placing ultracold atoms—atoms cooled just a tad above absolute zero—next to superconducting qubits. Getting ultracold atoms and superconducting qubits close enough to each other and tuned appropriately to communicate with one another was a difficult proposition that had never been attempted before. To aid in the quest, the team decided to trap atoms in a light trap produced just outside an optical fiber. To coax an optical fiber into carrying most of the light just outside itself, rather than at its center, it was necessary to stretch the fiber incredibly thin—more than a hundred times smaller than a human hair.

The bulk of Hoffman’s graduate school work was to devise a technique for stretching optical fibers to that size, while ensuring that they continued to guide most of the light along their path. The requirements were stringent—just a few stray, unguided photons would destroy the superconducting state if they hit it. Virtually all of the light needed to remain guided by the fiber, trapping atoms. Hoffman and his labmates devised a bespoke machine for pulling the fiber, and a careful protocol that resulted in fibers that could retain a record 99.95% of the light.

Although the process was at times arduous, Hoffman credits his time in graduate school with teaching him to persist through a difficult problem. “Practically, day to day,” Hoffman says, “I don't think graduate school was as exciting and rewarding as what I do now. But it did teach some very important lessons about determination and focus.”

A Taste of the Bigger Picture

After graduating from UMD (and receiving his fortuitous graduation present) in 2014, Hoffman was still unsure what he wanted to do. A former student from the same lab told him about a job at Booz Allen Hamilton. “He said ‘you will help advise on who should get funding and you will follow people's work’,” Hoffman says. “And I didn't actually really understand what any of that meant, but I was lucky because I ended up loving it.”

The job description turned out to be exactly correct. At Booz Allen, Hoffman worked as an assistant to program managers at DARPA, learning about the work funded through the programs, and advising. “Having worked on a very particular problem for six years,” Hoffman says, “it was just an entirely broader array of subjects. I was looking at a field as a whole and seeing where there are technology gaps and how you can close them, helping advise on or what needs investment.”

Hoffman reveled in seeing the bigger picture and picking out areas where fundamental science, slightly refined, could benefit technology. He got to learn about and support programs in a broad array of fields, including atomic physics, chemical spectroscopy, integrated photonics and positioning, navigation, and timing. He worked alongside DARPA program managers and becoming one himself gradually became a career goal.

Inspired in part by Harrison’s story in the Longitude book, the related topics of positioning, navigation, and timing quickly became among Hoffman’s chief interests, along with quantum sensing. As the navigation-related program he was supporting was coming to a close, Hoffman realized that he wanted to dig deeper. As a Booz Allen Hamilton contractor, he would have been reassigned to other fields, so he found a new role at the Army Research Laboratory (ARL) where he was able to do a mix of research work and program management.

While at ARL, Hoffman collaborated with several UMD professors at the Quantum Technology Center and the Joint Quantum Institute. He worked closely with JQI Fellow and QTC Director Ronald Walsworth on quantum sensing problems—Walsworth’s area of expertise. He also continued thinking about positioning, navigation, and timing and started a program to create smaller clocks for portable GPS devices.

Juggling Programs and People

During his time at ARL, Hoffman was developing his ideas about alternative ways to make affordable yet precise clocks. When the opportunity arose to interview for a program management role at DARPA, he pitched his plan to encourage new approaches to the problem. “I guess they liked it well enough because they hired me,” Hoffman says.

Hoffman’s H6 program is set to begin in the coming months. Since arriving at DARPA in 2021, however, Hoffman’s interests have only broadened. He now dreams of a program to create portable MRI’s that could be an affordable tool in every doctor’s office and is managing other programs in quantum sensing and communication.

What he finds particularly rewarding about his work is the collaboration with a huge range of experts in different fields, from scientists to generals. “It is a really broad experience,” Hoffman says. “Working with academia, national labs, industry, large businesses, small businesses—it’s really great to get all of those perspectives and be able to interact with leaders across multiple fields.”

To continue interacting with many partners to make the best possible scientific advances, Hoffman encourages a broad range of people to work with DARPA and support their mission. He says people can come in as contractors, subject matter experts, apply for small business funding through various mechanisms, apply for young faculty awards, or apply for research grants and more.

Overall, Hofmann has no regrets about his transition from in-the-lab scientific work to program management. “It's absolutely important and it's fascinating and rewarding to understand and just be motivated by the specific science, but it's always been helpful for me having the larger picture of where this would go in the long-term plan.”

Story by Dina Genkina

Calling All Experimentalists, Designers, Fixers and Tinkerers

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Category: Department News

Published: Thursday, January 26 2023 00:01

Two of the best-kept secrets in the University of Maryland’s Department of Physics are its Vortex Makerspace and a small class held in the makerspace that is dedicated to the practical skills needed for physics experimentation.

Since 2019, Professor Daniel Lathrop has taught a unique 400-level laboratory course in the Vortex Makerspace (formerly the Physics Welding Shop), which is tucked behind the John S. Toll Physics Building. Designed to teach students hands-on ways to bring their ideas to life, the class touches on topics such as carpentry, circuitry and 3D printing. Lathrop guides the students as they design, plan, build and demo their creations inspired by the semester’s physics lecture topics. But it’s not all about a student’s ability to build from scratch, Lathrop said.

“One thing I really wanted to accomplish with this class was to expose students to skills that they wouldn’t usually come across in their conventional classroom studies,” Lathrop explained. “That not only includes how to make things with their hands but also how to develop soft skills like leadership, budgeting, communication and teamwork—all qualities that are needed in real-life careers in physics.”

To simulate the kinds of situations, goals and challenges that physics experimentalists often encounter, Lathrop wove together 12 weeks of interactive lectures, field trips, training sessions and demonstrations. As his unique lesson plans for the class quickly spread by word of mouth, physics majors eager for a more hands-on learning experience registered for the class.

One of those students, Alexandra Pick-Aluas (B.S. ’22, physics), first heard glowing reviews about Lathrop’s class from two friends and was intrigued by the prospect of a lab elective that could give her a sneak peek into the professional future she hoped to pursue. She realized quickly that the class was unlike any she’d ever taken. 

“We were given an introduction to welding, which was obviously something I never tried before,” Pick-Aluas explained. “I learned how to weld pieces of metal together and got to see the difference in outcomes for the different metals I used. For example, aluminum is really easy to melt and that’s one reason why it’s a notoriously difficult metal to weld. It’s one thing to read about it, but it’s a much more enlightening experience to actually see it in action in front of me.”PHYS 499X students demonstrate their Spring 2022 semester project, a liquid nitrogen-cooled superconducting loop. From left to right: Peiyu Qin, Alexandra Pick-Aluas, Meyer Taffel, Noah Doney, Ankith Rajashekar, Brian Robbins, and Dylan Christopherson. Image courtesy of Daniel Lathrop.

Welding was just one skill Pick-Aluas developed during the class. For their final project, Pick-Aluas and her group members built a superconducting loop—an infinitely flowing electric current with no power source—with materials like scrap metal, a bicycle wheel spoke and superconducting tape. Guided by Lathrop, they designed a suitable prototype within a limited budget, ordered their required materials from specialized vendors, constructed their design and wrote a manual explaining how their project functioned.  

“Even though our project didn’t exactly work the way we originally wanted it to, the entire process it took to make the superconducting loop is something I’ll always remember,” Pick-Aluas said. “Professor Lathrop says that in reality, failures and setbacks should be expected before making progress.”

She hopes that more physics majors take PHYS 499X before they graduate. For Pick-Aluas, who is now assisting Lathrop in his lab as she prepares for graduate school, the expertise she gained from the course helped shape her own career goals. 

“At first, I was a little intimidated, but the class made me feel a lot more comfortable with these skills. Potentially applying them on the job is a little less daunting to me now,” Pick-Alaus explained. “PHYS 499X is a really good overview of what you can expect in a real-life physics-related profession, whether it’s in academia or in industry.” 

Beyond the class, physics majors can also use the Vortex Makerspace—which is housed within the same single-room building as PHYS 499X—for all their experimentalist aspirations. Thanks to key efforts from UMD Physics Director of Education Donna Hammer, Vortex provides a dedicated time and place for students to work on meaningful projects of their own. Equipped with saws, welders, wires, wrenches and other knickknacks ready for students to use, the makerspace also encourages students to walk in and chat with Vortex’s ‘shop managers’ if they need additional guidance, resources or someone to simply bounce ideas off of.

“We’re open four afternoons a week to anyone during the semester—no experience or background necessary,” said Jake Lyon, a senior physics major and vice president of the Vortex Makerspace. “Vortex frequently holds training sessions and workshops for a variety of topics, like intro into basic coding or circuitry.”

Jake Lyon (right) teaches a student how to solder a simple circuit at the UMD Physics Vortex Makerspace.Lyon became involved with the makerspace as a sophomore. Over the next few years, he attended a variety of training sessions and eventually developed an arsenal of handy skills from 3D printing to soldering. Then he tested this newly acquired knowledge, applying it to the projects he took on at the makerspace, including his personal favorite, fixing a broken megaphone. He believes taking the megaphone apart, figuring out how it worked and diagnosing what went wrong was an experience that will stay with him long after he graduates.

“The Vortex is a fantastic place to learn and get comfortable with the basic parts of fabrication with the right equipment while also getting to know the physics makers community,” Lyon said. “We facilitate learning but try to encourage teamwork and communication with everyone as well.”

In addition to the activities held during the semester, the Vortex Makerspace also offers a series of summer programs, including the Physics Makers Camp for high school students looking to get a head start on creative thinking and design, run by Outreach Coordinator Angel Torres. And although Vortex is run by physics undergraduates, Lyon said the organization welcomes anyone who wants to bring a project to life.

“We have a good lineup of ideas for workshops in the spring semester, so anyone—including non-physics majors—looking to acquire a new handy skill or two is welcome to stop by,” Lyon said. “Just bring an idea and we’ll bring the tools.” 

Written by Georgia Jiang