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Ruomu Zhang, a senior double-majoring in physics and mathematics, has been selected to receive the Stephen Halley White Undergraduate Research Award in recognition of his exceptional honors research project. The award is one of the top honors for graduating physics and engineering physics students in the Department of Physics.

The award was established in 2013 by alumnus Dr. Stephen White (Phys’63) to recognize exceptional undergraduate research projects. During his undergraduate studies at CU Boulder, Dr. White’s research experiences made an impact on his future career and led him to create the award.����

Finding his path��

The son of two biologists, Zhang always figured he would pursue a STEM-related career. In high school, his physics teacher inspired him to choose physics. Initially, he was drawn to figuring out how the universe works and thought he might conduct particle physics research.��

Zhang enrolled at CU Boulder to study physics and math. In his first year, getting involved in programs like CU-Prime helped Zhang prepare for what it would be like to be a scientist.����

Designing mechanical oscillators��

Zhang joined Professor and JILA Fellow Cindy Regal’s lab during his freshman year, just as the lab was starting a new project.��

His research focused on mechanical oscillators, tiny two-dimensional membranes that bend in response to external effects like magnetic and electric fields, and temperature changes. Zhang designed and analyzed oscillators that form the basis of micromechanical sensors.��

As a bassist himself, Zhang likens the oscillators to a guitar string. By listening to the pitch of a string, you can figure out how much someone has turned the tuning peg.����

“That’s exactly what we’re doing,” says Zhang, “but instead of someone turning the tuning peg, it’s an electric field, radiation, or a magnetic field. We are measuring the frequencies—the pitch—to figure out what happened.”��

Designing an oscillator is complex, Zhang says, but he enjoyed the freedom of the design process.����

“There’s a lot of intuition involved,” says Zhang. “The field has developed great mathematical models for many oscillator designs. But because you can pattern these two-dimensional membranes however you want, you can’t analytically derive the best design. People are constantly coming up with new design paradigms – there is no fixed recipe."��

Mechanical oscillators are used in everyday technology like phones, Zhang explains. Microphones, accelerometers, and clocks all rely on various types of oscillators.��

In Regal’s lab, the team is working to develop an improved far infrared sensor. “Right now, it's hard to detect far infrared radiation with high sensitivity without cryogenic cooling of the sensor,” says Zhang. “We are trying remove cryogenic cooling and at the same time make a really good sensor.”��

The project's potential for real-world application was a major draw for Zhang. “I can see a good timeline at the end where there might actually be a usable sensor,” he says.��

Improved sensors could be put on satellites, where they can detect faint radiation from a distant star, or improve global monitoring of temperature fluctuations, for example.����

Research earns top honors����

Zhang was awarded a summa cum laude designation for his research project by the College of Arts & Sciences Honors Council. He was then selected to receive the Stephen Halley White Undergraduate Research Awards by the Physics Honors Council Representatives.��

Zhang’s written thesis placed the work within an unusually broad technical context, according to Regal. “Ruomu developed a strong experimental intuition for calibration and noise, enabling substantive work in both analysis and device design,” she says.��

After joining the Regal lab in his freshman year, Zhang spent the first several years helping set up the experiment. In the last year, they started to get some exciting results which were . As a result, Zhang says it meant a lot that people recognized the effort the team put into the project.����

“Having the committee recognize my work with this award is very rewarding,” says Zhang.��

Jun Ye, professor adjoint of physics and JILA fellow, served as the Physics Honors Council Representative and was impressed by Zhang’s work, highlighting the range of “new ideas and designs to detailed measurement and analysis.” Ye adds, “Ruomu was among several outstanding honors graduates this semester, and this really speaks to the high standard of CU’s physics department.”��

Best advice and what’s next��

Zhang’s best advice for future students? Be brave. And get involved. He admits he didn’t know much about this field before he joined Regal’s lab, but he didn’t let that deter him from applying.����

“Undergraduate research really helped me find what I wanted to do in the future,” says Zhang.��

Support from the Undergraduate Research Opportunities Program (UROP) helped Zhang secure funding for working in the Regal lab, but it was more than that.����

“Getting funding and having that structure—the practice of applying for funding and going through the entire funding process—was also really useful,” Zhang says. “I foresee a lot of that in my future.”��

Joining Quantum Scholars in his junior year exposed Zhang to fields outside of his specialty, broadening his perspective.����

“Having Quantum Scholars invite speakers from different fields, industry, and policy making helped me form a better perspective on the entire field of physics and how it relates,” explains Zhang. “It also helped me find a really good community at CU.”��

After graduating this semester, Zhang will pursue his PhD in quantum science and engineering at the �Թ��� of Chicago.����