Maryland Quantum-Thermodynamics Hub Secures Funding for Three More Years

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Category: Department News

Published: Monday, September 15 2025 00:01

From Lab Bench to Launch Pad

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Category: Department News

Published: Monday, September 08 2025 01:40

When University of Maryland physics major Dhruv Agarwal first learned about phase change materials—substances that maintain stable temperatures in extreme conditions—in his freshman year, he never imagined the concept would eventually take him to the stars. Now a junior, Agarwal uses his expertise in the subject to lead a team of 20 undergraduates building technology that NASA might one day launch into orbit.

Dhruv Agarwal As a project lead for UMD’s Satellite Component Fabrication (SatFab) team, Agarwal oversees one of the most ambitious undergraduate student-led projects on campus: constructing a complete CubeSat from scratch. About the size of a small loaf of bread, SatFab’s mini satellite will house cutting-edge thermal management technology that could revolutionize how spacecraft handle the extreme temperatures of space. 

“CubeSats are small satellites used to carry out Earth observation tasks, perform technology demonstrations or carry experimental payloads,” Agarwal explained. “Our team’s CubeSat is a 3U—meaning a 10-by-10-by-30-centimeter satellite—that will perform the latter two tasks. It’ll have a completely in-house GPS and a novel phase change material-based thermal control system that we designed. We’re hoping to launch our CubeSat through NASA’s CubeSat Initiative, which will send CubeSats to the International Space Station before releasing them into lower Earth orbit.”

Building tomorrow’s satellites today

Agarwal’s journey to satellite engineering wasn’t a straightforward one. Space technology wasn’t even on his radar until he was able to work on a phase change material experiment in 2023 with Aerospace Engineering Senior Lecturer Eric Silk, a faculty advisor for UMD’s Students for the Exploration and Development of Space (SEDS) campus organization. For Agarwal, the opportunity—and a SEDS recruitment email—instantly kick-started his multiyear adventure with space tech.Phase change material experiment.

“I never had an interest in engineering or space, but I am interested in figuring out how things work, which is why I decided to pursue physics,” Agarwal said. “My experience of working with Dr. Silk and my team on the SatFab project ignited my passion for space tech. In turn, I had the chance to apply my knowledge of physics principles in a meaningful way.” 

Working from the ground up, the SatFab team are designing and building every component of the CubeSat, including its exterior shell, communication system, custom-made GPS and novel thermal energy storage system. Agarwal led the team’s efforts in developing the thermal control system, which was designed to be simpler, less expensive and less energy-intensive than existing cooling mechanisms currently used in satellites. 

“Phase change materials are substances that store and release large amounts of energy when they transition between different states, like ice melting into water,” Agarwal explained. “We developed a system that uses this principle to regulate satellite electronics temperatures.”

Agarwal noted that as phase change material on the CubeSat absorbs heat (like when the satellite is in sun-view) and transitions from solid to liquid, it maintains a steady temperature even as it stores excess energy. When temperatures drop (such as when the satellite is in Earth’s shadow), the material solidifies and releases the stored heat back to the satellite’s electronics. This special design allows electronics to be kept in their operating temperature range while minimizing fluctuation, thereby ensuring the satellite’s optimal performance and extending its longevity. 

Developing a working prototype wasn’t easy, Agarwal admitted. With guidance from Silk, the SatFab group also had an overwhelming amount of freedom to architect their experiments despite initially not having the expertise or experience to do so. They learned on the job, designing and redesigning experiments and vigorously testing each component. 

“By developing our systems in-house and making them open source, we hope that we’re laying the ground for future student projects,” he said. “It’s an ongoing project that everyone contributes to.”

Reaching new heights

The SatFab team is already working with partners like aerospace firm Amphenol CIT to ensure that the satellite meets professional reliability standards. Agarwal anticipates that the CubeSat’s components will soon be able to be tested via balloon payloads to simulate flight conditions. 

This semester, Agarwal plans to draft his team’s NASA CubeSat proposal, write the final research manuscript for CubeSat’s thermal control system project, and prepare to present it at the 2026 American Institute of Aeronautics and Astronautics’ SciTech Forum in January. He expects for the team’s CubeSat to launch in late 2027 or early 2028.

“Our work was recently accepted for presentation at SciTech, so I’m excited to enter the next phase of the project. We’ve made a lot of progress, but there’s still a lot more to be done,” Agarwal said. “We need more students with a passion for problem-solving on our team than ever, especially those with physics and engineering backgrounds.”  

As a physics major, Agarwal never thought he’d lead a team of engineers or perform administrative tasks like budget or resource management but now sees the experience as invaluable and applicable to any lab or office. He hopes that other physics majors will look to explore less traditional paths as he did—and discover a new way to grow and achieve success.  

“I’m incredibly thrilled at the prospect of our experiment possibly being launched into space, especially because we’re all undergraduate students,” he added. “The fact that my team’s work can culminate in something so fantastic and actually create a lasting contribution to space engineering is something I’ll always remember.”

Written by Georgia Jiang

Researchers Imagine Novel Quantum Foundations for Gravity

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Category: Research News

Published: Wednesday, September 03 2025 01:40

Questioning assumptions and imagining new explanations for familiar phenomena are often necessary steps on the way to scientific progress.

For example, humanity’s understanding of gravity has been overturned multiple times. For ages, people assumed heavier objects always fall quicker than lighter objects. Eventually, Galileo overturned that knowledge, and Newton went on to lay down the laws of motion and gravity. Einstein in turn questioned Newton’s version of gravity and produced the theory of general relativity, also known as Einstein's theory of gravity. Einstein imagined a new explanation of gravity connected to the curvature of space and time and revealed that Newton’s description of gravity was just a good approximation for human circumstances.Researchers have proposed new models of how gravity could result from many quantum particles interacting with massive objects. In the image, the orientation of quantum particles with spin (the blue arrows) are influenced by the presence of the masses (represented by red balls). Each mass causes the spins near it to orient in the same direction with a strength that depends on how massive it is (represented by the difference in size between the red balls). The coordination of the spins favor objects being close together, which pulls the masses toward each other. (Credit: J. Taylor)

Einstein’s theory of gravity has been confirmed with many experiments, but scientists studying gravity at the tiniest scales have uncovered lingering mysteries around the ubiquitous force. For miniscule things like atoms or electrons, the rules of quantum physics take over and interactions are defined by discrete values and particles. However, physicists haven’t developed an elegant way to definitively combine their understanding of gravity with the reality of quantum physics experiments. This lack of a quantum explanation makes gravity stand out as an enigma among the four fundamental forces­—the forces of gravity, the electromagnetic force, the strong nuclear force and the weak nuclear force. Every other force, like friction, pressure or tension, is really just one or more of those four forces in disguise.

To unravel gravity’s lingering idiosyncrasies, researchers are designing new experiments and working to identify the foundations of gravity at the quantum scale. For decades, scientists have been proposing alternative models, but none has emerged as the definitive explanation.

“We know how electromagnetism works,” says Daniel Carney, a scientist at Lawrence Berkeley National Laboratory (LBNL) who formerly worked as a postdoctoral researcher at JQI and the Joint Center for Quantum Information and Computer Science (QuICS). “We know how the strong and weak nuclear forces work. And we know how they work in quantum mechanics very precisely. And the question has always been, is gravity going to do the same thing? Is it going to obey the same kind of quantum mechanical laws?”

The three other fundamental forces are each associated with interactions where quantum particles pop into existence to transmit the force from one spot to another. For instance, electromagnetic forces can be understood as particles of light, called photons, moving around and mediating the electromagnetic force. Photons are ubiquitous and well-studied; they allow us to see, heat food with microwave ovens and listen to radio stations. 

Physicists have proposed that similar particles might carry the effect of gravity, dubbing the hypothetical particles gravitons. Many researchers favor the idea of gravitons existing and gravity following the same types of quantum laws as the other three fundamental forces. However, experiments have failed to turn up a single graviton, so some researchers are seeking alternatives, including questioning if gravity is a fundamental force at all. 

What might the world look like if gravity is different, and gravitons are nowhere to be found? In an article published in the journal Physical Review X on August 11, Carney, JQI Fellow Jacob Taylor and colleagues at LBNL and the University of California, Berkeley are laying the early groundwork for graviton-free descriptions of gravity. They presented two distinct models that each sketch out a vision of the universe without gravitons, proposing instead that gravity emerges from interactions between massive objects and a sea of quantum particles. If the models prove to be on the right track, they are still just a first step. Many details, like the exact nature of the quantum particles, would still need to be fleshed out.

In the new proposals, gravity isn’t a fundamental force like electromagnetism but is instead an emergent force like air pressure. The force created by air pressure doesn’t have the equivalent of a photon; instead, pressure results from countless gas molecules that exist independent of the force and behave individually. The unorganized molecules move in different directions, hit with different strengths, and sometimes work against each other, but on a human scale their combined effect is a steady push in one direction. 

Similarly, instead of including discrete gravitons that embody a fundamental force of gravity, the new models consider many interacting quantum particles whose combined behavior produces the pull of gravity. If gravity is an emergent force, researchers need to understand the quirks of the collective process so they can be on the lookout for any resulting telltale signs in experiments. 

The two models the group introduced in the paper are intentionally oversimplified—they are what physicists call toy models. The models remain hazy or flexible on many details, including the type of particles involved in the interactions. However, the simplicity of the models gives researchers a convenient starting point for exploring ideas and eventually building up to more complex and realistic explanations.

“We’re using these toy models … because we understand that there are many differences between this sort of microscopic model we proposed here and a model that is consistent with general relativity,” says Taylor, who is also a QuICS Fellow and was also a physicist at the National Institute of Standards and Technology when the research was conducted. “So rather than assume how to get there, we need to find the first steps in the path.”

The initial steps include laying out potential explanations and identifying the signature each would produce in experiments. Both Taylor and Carney have spent about a decade thinking about how to make grounded predictions from quantum theories of gravity. In particular, they have been interested in the possibility of gravity resulting from many particles interacting and coming to equilibrium at a shared temperature. 

They were inspired by research by University of Maryland Physics professor Ted Jacobson that hinted at black holes and Einstein’s theory of gravity being linked to thermodynamics. Thermodynamics is the physics of temperatures and the way that energy, generally in the form of heat, moves around and influences large groups of particles. Thermodynamics is crucial to understanding everything from ice cream melting to stars forming. Similarly, the researchers think a theory of gravity might be best understood as the result of many interacting particles producing a collective effect tied to their temperature.

However, while there are theoretical clues that a thermodynamic foundation of gravity might exist, experiments haven’t provided researchers with any indication of what sort of quantum particles and interactions might be behind an emergent form of gravity. Without experimental evidence supporting any choice, researchers have been free to propose any type of quantum particle and any form of interaction to be the hypothetical cause of gravity. 

Taylor and Carney started with the goal of recreating the basic gravitational behaviors described by Newton instead of immediately attempting to encompass all of Einstein’s theory. A key feature described by Newton is the very particular way that gravity gets weaker as separation increases: Gravity always falls off at a rate proportional to the square of the distance between two objects, called the inverse-square force law. The law means that as you move away from the Earth, or some other mass, its gravitational pull decreases at a quicker and quicker rate. But identifying quantum interactions with matter that could create even that general behavior wasn’t trivial, and that first step to imagining a new form of gravity eluded researchers.

In the fall of last year, Carney and Manthos Karydas, a postdoctoral researcher working with Carney at LBNL who is also an author of the paper, worked out a simple model of quantum interactions that could capture the needed law. After Carney discussed the idea with Taylor, they were able to formulate a second distinct model with an alternative type of interaction.

“Dan came into my office and outlined the basic mechanism on the chalkboard,” Karydas says. “I found it very elegant, though his initial model gave a constant force between the masses. With some refinement, we managed to recover the inverse-square force law we had been aiming for.”

Both models assume there are many particles at a given temperature that can interact with all the masses included in the model. Unlike gravitons, these new particles can be understood as having a more permanent independent existence independent from gravity.

For convenience, they created the models where the sea of quantum particles were all spins, which behave like tiny magnets that tend to align with magnetic fields. A vast variety of quantum objects can be described as spins, and they are ubiquitous in quantum research.

In one of the models, which the team called the local model, the quantum spins are spread evenly on a grid, and their interactions depend on their position relative to both the masses and each other. Whenever a massive object is placed somewhere on the grid it interacts with the nearby spins making them more likely to point in the same direction. And when it moves through the crowd, a cloud of quantum influence accompanies it. 

The clouds of coordination around a mass can combine when two masses approach one another. The combination of their influence into the same space decreases the energy stored in the surrounding quantum particles, drawing the masses toward each other.

In contrast, the original model that Carney and Karydas developed doesn’t paint a clear picture of how the spins are distributed and behave in space. They were inspired by the way waves behave when trapped between objects: When light is trapped between two mirrors or sound waves are trapped between two walls, only waves of specific lengths are stable for any particular spacing between the objects. You can define a clear set of all the waves that neatly fit into the given space.

While the particles in the model are spins and not waves, properties of their interactions resemble waves that must neatly fit between the two masses. Each spin interacts with every possible pair of masses in this wave-like way. The group dubbed this model the “non-local model” since the interactions don’t depend on where the quantum particles or masses are located individually but just on the distance between the masses. Since the positions of the spins don’t influence anything, the model doesn’t describe their arrangement in space at all. The group showed that the appropriate set of wave-like interactions can make the quantum particles store less energy when objects are close together, which will pull the objects towards each other.

“The nonlocal model seemed kind of bizarre when we first were writing it down,” Taylor says. “And yet, why should we guess which one is correct? We don't think either of them is correct in the fundamental sense; by including them both, we're being clear to the physics community that these are ways to get started without presupposing where to go.”

The particles being spins isn’t an essential feature of the models. The team demonstrated that other types of particles are worth considering by redoing their work on the non-local model for an alternative type of particle. They showed that the wave-like interactions could also produce gravity if the proposed particles were quantum harmonic oscillators, which can bounce or swing between states similar to springs and pendulums. 

The group’s calculations illustrate that both types of quantum interactions could produce a force with the signature behavior of Newton’s gravity, and the team described how the details of the interactions can be tailored so that the strength of the force matches what we see in reality. However, neither model begins to capture the intricacies of Einstein’s theory of gravity. 

“This is not a new theory of gravity,” Taylor says. “I want to be super clear about this. This is a way to reason about how thermodynamic models, including possibly those of gravity, could impact what you can observe in the lab.”

Despite the intentional oversimplification of both models, they still provide insights into what results researchers might see in future experiments. For instance, the interactions of the particles in both models can impact how much noise—random fluctuations—gravity imparts on objects as it pulls on them. In experiments, some noise is expected to come from errors introduced by the measurement equipment itself, but in these models, there is also an inescapable amount of noise produced by gravity. 

The many interactions of quantum particles shouldn’t produce a steady pull of gravity but instead impart tiny shifts of momentum that produce the gravitational force on average. It is similar to the miniscule, generally imperceptible kicks of individual gas molecules collectively producing air pressure: Gravity in the models at large scales seems like a constant force, but on the small scale, it is actually the uneven pitter patter of interactions tugging irregularly. So as researchers make more and more careful measurements of gravity, they can keep an eye out for a fluttering that they can’t attribute to their measurement technique and check if it fits with an emergent explanation of gravity. 

While the two models share some common features, they still produce slightly different predictions. For instance, the non-local model only predicts noise if at least two masses are present, but the local model predicts that even a solitary mass will constantly be buffeted by random fluctuations.

Moving forward, these models need to be compared to results from cutting-edge experiments measuring gravity and improved to capture additional phenomena, such as traveling distortions of space called gravitational waves, that are described by Einstein’s theory of gravity. 

“The clear next thing to do, which we are trying to do now, is make a model that has gravitational waves because we know those exist in nature,” Carney says. “So clearly, if this is going to really work as a model of nature, we have to start reproducing more and more things like that.”

Story by Bailey Bedford

In addition to Carney, Karydas and Taylor, co-authors of the paper include Thilo Scharnhorst, a graduate student at the University of California, Berkely (UCB), and Roshni Singh, a graduate student at UCB and LBNL.

Solving a Decades-long Solar Flare Mystery

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Category: Department News

Published: Wednesday, September 03 2025 01:40

For almost half a century, scientists have been scratching their heads over one of the strangest and most inexplicable phenomena to occur on the sun. During certain explosive events like solar flares, helium-3 (an extremely rare isotope normally found in tiny quantities) suddenly becomes dramatically more abundant than usual as it gets blasted toward Earth. Sometimes, it even outnumbers helium-4, the most common variant of the element—a complete reversal of expectations. 

Now, Anna Fitzmaurice, a physics Ph.D. student at the University of Maryland, may have brought scientists a step closer to solving this cosmic puzzle. Working with Distinguished University Professor of Physics James Drake, Fitzmaurice narrowed down potential culprits for the abnormally high amount of helium-3 during solar flares by focusing on a fundamental process called magnetic reconnection. Anna Fitzmaurice

“Magnetic reconnection is a driving force behind solar flares and their interactions with Earth's magnetic field, such as what we see as the northern and southern lights,” Fitzmaurice explained. “Although the sun’s magnetic reconnection and the helium being released toward Earth usually isn’t harmful to us, it influences space weather and potentially impacts our satellites, power grids and even astronauts we send up to space. Studying this phenomenon can help us predict and maybe even prepare for when things get rough.”

A new approach to an old problem

Previous scientific theories focused on high-energy electrons (negatively charged particles) somehow creating the right conditions to accelerate helium-3. But based on previous magnetic reconnection research,  Drake’s group thought that the real drivers might be just the opposite:  they believed that protons (positively charged particles) were more likely to be able to transfer energy into helium-3, superheating the rare isotope and pushing it past helium-4 toward Earth. 

To test this theory, Fitzmaurice developed a detailed simulation of solar environments by modeling a uniform magnetic field containing cold background protons and hot, energetic particles streaming through them like jets.

“Imagine if you had a pond full of water. If you shoot a hose through this pond, you’d get all these ripples and waves in the water,” Fitzmaurice explained. “Something similar happens when you shoot high-energy protons through a background of still, non-moving protons.” 3He acceleration. Credit: Anna Fitzmaurice.

Fitzmaurice found that magnetic reconnection on the sun created beams of fast-moving particles, and these particles generated two types of plasma waves that heated helium-3 to extremely high temperatures—nearly 20 times hotter than its original temperature. The  temperatures were so intense that superheated helium-3 could move into regions of the sun where particles get accelerated and eventually shot toward Earth. However, helium-4 experienced less heating, so it stayed behind this speed threshold and was unable to reach the acceleration zones. Fitzmaurice’s research resulted in two recent papers, one published in The Astrophysical Journal and the other in the journal Physics of Plasmas. 

“My  simulations indicate that helium-3 enhancement events are probably much more common than we previously thought,” Fitzmaurice said. “This suggests that there’s some underlying physical process that’s a fundamental feature of solar flare physics rather than a rare anomaly. Learning more about these fundamental processes can help us better understand how the universe works. We can apply this to many different contexts, including learning about environments around black holes and neutron stars, or how the sun’s activity influences life on Earth and humans.”

From family stargazer to solar flare detective

Fitzmaurice feels like she’s come a long way in her journey as an astrophysicist. Growing up in a family where “no one was very science-minded,” she often reflects on how her serendipitous path to astrophysics began—with her father, who often took her to watch rocket launches from NASA’s Wallops Visitor Center in Virginia when she was growing up. 

“I feel pretty lucky to have someone who really fed my curiosity about space as a kid,” Fitzmaurice explained. “We would go as a family to watch meteor showers and rocket launches. He pointed out stars and planets in the night sky. It was because of those experiences that I ‘accidentally’ ended up studying the sun during my undergrad at Catholic University, even though it really wasn’t my original plan in college.”  

Looking back, Fitzmaurice believes she couldn’t have picked a better time to study the sun and its fiery storms. She initially began her research around the 2017 total solar eclipse, which captured the attention of millions of Americans, and has observed many unique solar events since. Now in her final year of her Ph.D. program, Fitzmaurice hopes to connect her theoretical breakthrough about helium-3 to real satellite measurements and essentially prove that her computer models match what actually happens deep in space. She hopes her work will help scientists understand the fundamental physics behind solar flares and bring researchers closer to predicting when and how violently the sun might act up.

“It’s honestly been a very exciting time for me and other solar scientists,” Fitzmaurice said. “We’re now nearing the end of the solar maximum, the peak of the sun’s 11-year activity cycle and when there are more frequent and violent solar flares. With satellites like the Parker Solar Probe and Solar Orbiter, we’re getting closer to the sun than ever before and learning things we would never have expected.”