Research

New discovery shows how molecules can mute heat like music

Alexander James Servantez — Wed, 07 May 2025 03:00:00 +0000

New discovery shows how molecules can mute heat like music Alexander Jame鈥� Tue, 05/06/2025 - 21:00

Alexander Servantez

Imagine you are playing the guitar鈥攅ach pluck of a string creates a sound wave that vibrates and interacts with other waves.

Now shrink that idea down to a small single molecule, and instead of sound waves, picture vibrations that carry heat.

Ultra-high vacuum scanning probe setup modified by the Cui Research Group to conduct thermal microscopy experiments.

A team of engineers and materials scientists in the Paul M. Rady Department of Mechanical Engineering at CU Boulder has recently discovered that these tiny thermal vibrations, otherwise known as phonons, can interfere with each other just like musical notes鈥攅ither amplifying or canceling each other, depending on how a molecule is "strung" together.

Phonon interference is something that鈥檚 never been measured or observed at room temperature on a molecular scale. But this group has developed a new technique that has the power to display these tiny, vibrational secrets.

The breakthrough study was led by Assistant Professor Longji Cui and his team in the Cui Research Group. Their work, funded by the National Science Foundation in collaboration with researchers from Spain (Instituto de Ciencia de Materiales de Madrid, Universidad Aut贸noma de Madrid), Italy (Istituto di Chimica dei Composti Organometallici) and the CU Boulder Department of Chemistry, was recently published in the journal Nature Materials.

The group says their findings will help researchers around the world gain a better understanding of the physical behaviors of phonons, the dominant energy carriers in all insulating materials. They believe one day, this discovery can revolutionize how heat dissipation is managed in future electronics and materials.

鈥淚nterference is a fundamental phenomenon,鈥� said Cui, who is also affiliated with the Materials Science and Engineering Program and the Center for Experiments on Quantum Materials. 鈥淚f you have the capability to understand interference of heat flow at the smallest level, you can create devices that have never been possible before.鈥�

The world鈥檚 strongest set of ears

Cui says molecular phononics, or the study of phonons in a molecule, has been around for quite some time as a primarily theoretical discussion. But you need some pretty strong ears to 鈥渓isten鈥� to these molecular melodies and vibrations first-hand, and that technology just simply hasn鈥檛 existed.

A sneak peek into the ultra-high vacuum scanning probe microscopy setup used to conduct molecular measurements.

That is, until Cui and his team stepped in.

The group designed a thermal sensor smaller than a grain of sand or even a sawdust particle. This little probe is special: it features a record-breaking resolution that allows them to grab a molecule and measure phonon vibration at the smallest level possible.

Using these specially designed miniature thermal sensors, the team studied heat flow through single molecular junctions and found that certain molecular pathways can cause destructive interference鈥攖he clashing of phonon vibrations to reduce heat flow.

Sai Yelishala, a PhD student in Cui鈥檚 lab and lead author of the study, said this research using their novel scanning thermal probe represents the first observation of destructive phonon interference at room temperature.

In other words, the team has unlocked the ability to manage heat flow at the scale where all materials are born: a molecule.

鈥淟et鈥檚 say you have two waves of water in the ocean that are moving towards each other. The waves will eventually crash into each other and create a disturbance in between,鈥� Yelishala said. 鈥淭hat is called destructive interference and that is what we observed in this experiment. Understanding this phenomenon can help us suppress the transport of heat and enhance the performance of materials on an extremely small and unprecedented scale.鈥�

Tiny molecules, vast potential

Developing the world鈥檚 strongest set of ears to measure and document never-before-seen phonon behavior is one thing. But just what exactly are these tiny vibrations capable of?

PhD student and lead author of the study Sai Yelishala (right), along with Postdoctoral Associate and second author Yunxuan Zhu (left). Both are members of the Cui Research Group led by Assistant Professor Longji Cui.

鈥淭his is only the beginning for molecular phononics,鈥� said Yelishala. 鈥淣ew-age materials and electronics have a long list of concerns when it comes to heat dissipation. Our research will help us study the chemistry, physical behavior and heat management in molecules so that we can address these concerns.鈥�

Take an organic material, like a polymer, as an example. Its low thermal conductivity and susceptibility to temperature changes often poses great risks, such as overheating and degradation.

Maybe one day, with the help of phonon interference research, scientists and engineers can develop a new molecular design. One that turns a polymer into a metal-like material that can harness constructive phonon vibrations to enhance thermal transport.

The technique can even play a large role in areas like thermoelectricity, otherwise known as the use of heat to generate electricity. Reducing heat flow and suppressing thermal transport in this discipline can enhance the efficiency of thermoelectric devices and pave the way for clean energy usage.

The group says this study is just the tip of the iceberg for them, too. Their next projects and collaborations with CU Boulder chemists will expand on this phenomenon and use this novel technique to explore other phononic characteristics on a molecular scale.

鈥淧honons travel virtually in all materials,鈥� Yelishala said. 鈥淭herefore we can guide advancements in any natural and artificially made materials at the smallest possible level using our ultra-sensitive probes.鈥�

Assistant Professor Longji Cui and his team in the Cui Research Group have developed a new technique that allows them to measure phonon interference inside of a tiny molecule. They believe one day, this discovery can revolutionize how heat dissipation is managed in future electronics and materials.

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An artistic rendering showing thermal phonon interference in a molecule, otherwise known as "a molecular song."

PhD alum spent 45 days isolated in space. Well, kind of

Alexander James Servantez — Tue, 01 Apr 2025 22:18:30 +0000

PhD alum spent 45 days isolated in space. Well, kind of Alexander Jame鈥� Tue, 04/01/2025 - 16:18

Alexander Servantez

Robert Wilson stepped foot inside the Human Exploration Research Analog (HERA) facility with just a bag of clothes, some headphones and a journal. He looked around his new home鈥攁 650-square-foot closed habitat with two narrow floors and one small loft.

Robert Wilson (PhDMechEngr'20) and his fellow crew members during the 45-day simulated mission to Mars.

Wilson, a PhD graduate from the Paul M. Rady Department of Mechanical Engineering, was living every child鈥檚 dream. For the next 45 days, he and a team of three crew members from around the world were embarking on a simulated mission to Mars.

Their NASA-sponsored mission was simple: live and work like an astronaut. But life in the deep space domain isn鈥檛 as glamorous as it seems, even if it鈥檚 just a simulation.

鈥淲hen the door was sealed shut behind me, things got real, fast,鈥� Wilson said.

The HERA research habitat, housed at NASA鈥檚 Johnson Space Center in Houston, is one of the country鈥檚 premier locations for isolation and confinement research. Scientists across the nation use HERA studies to analyze the effects of deep space on human health and performance.

One day, insights gathered from HERA simulated missions could help guide the development of new, innovative strategies aimed at helping astronauts overcome challenges and perform complex tasks while in space. Maybe it鈥檚 a series of models that can predict an astronaut鈥檚 levels of stress and fatigue, or inform crew dynamics so they can work better as a team.

For Wilson, maybe it鈥檚 something more than that. Think of TARS, Matthew McConaughey鈥檚 robot companion in the movie Interstellar, who uses a vast bank of knowledge on human behavior to assist the crew during their cosmic mission.

鈥淭here鈥檚 a lot left on the table when it comes to studying and using biometric data,鈥� said Wilson. 鈥淭he goal is to provide artificial intelligence systems with better data on humans to help them make more informed decisions.鈥�

Experiencing space without ever leaving the ground

Wilson, currently a senior researcher at Johns Hopkins University in Maryland, received his PhD from CU Boulder in 2020. His research focused on analyzing and modeling one of the hardest populations in the world to work with: people.

Wilson standing in front of the HERA facility.

鈥淚 was mostly interested in biometric data鈥攈ow we can use it to answer questions and inform our decisions,鈥� Wilson said. 鈥淏ut it鈥檚 the human element that makes it difficult. People are 鈥榮quishy鈥� and engineering with 鈥榮quishy鈥� things is very hard. Not all things are generalizable across all people, and being able to solve problems in this space relies on our ability to gather reasonable and consistent data about how humans behave or perform.鈥�

There are other variables, such as environment, that make collecting human data more difficult, as well. Few humans have experienced the isolated no-man鈥檚-land that we call outer space, and the data we have collected is too little to represent the infinity and beyond.

That鈥檚 why Wilson and others are choosing to take matters into their own hands as research volunteers at the HERA facility in Houston.

鈥淲hen I was researching the HERA facility and learning what it takes to be a test subject, I realized that I fit all of the requirements. I could be data,鈥� said Wilson. 鈥淪o I applied just to see what happens. I got accepted, I went through physical evaluations, psychological evaluations and was lucky enough to be selected for the simulated Mars mission.鈥�

Wilson and his fellow crew members familiarized themselves with the habitat, completing a few weeks of training before the real mission was set to begin in November. They needed to be prepared to handle communication delays as they 鈥渁pproach鈥� Mars, maintain life support systems aboard the analog, and conduct the 18 different human health studies related to a spaceflight-like environment.

Once the team 鈥渢ook off,鈥� they were on their own. Other than a weekday Houston newspaper and a weekly family call, the crew was completely cut off from the outside world.

It was as if the vast unknown had suddenly become very small, and the only way to stay on track was through each other.

鈥淵ou really have to rely on the crew dynamics,鈥� Wilson said. 鈥淚 call it team maintenance. Not every day is a winning day. It鈥檚 about being open with each other and figuring out how to navigate the challenges.鈥�

Human-machine teaming in space and at home

Each of these simulated missions to Mars is just one small step for mankind. More missions must be completed and more data gathered in order for researchers to develop impactful tools for astronauts during space travel.

Wilson tinkering with some machinery in his HERA facility workspace.

For Wilson, these tools rely on a new, multidisciplinary field called human-machine teaming.

Picture your ordinary robot. It may have its own special capabilities that are useful to humans, but Wilson sees more. What if the next generation of human and robot teams operate under shared cognition鈥攖hey can understand each other and achieve a shared goal?

鈥淢aybe we can pair [astronauts] with a rover that has an idea of how they are doing,鈥� said Wilson. 鈥淚t can still keep track of their life support systems, but it can also help them make informed decisions based on their levels of stress and fatigue.鈥�

Wilson says robot companions equipped with these types of AI systems can be extremely impactful back on Earth, too. Believe it or not, outer space isn鈥檛 the only environment that poses great risk to humans.

鈥淭here are people everywhere, in all kinds of environments,鈥� Wilson said. 鈥淢aybe these systems can help people in areas where temperatures get really hot or really cold, like Antarctica. Maybe it鈥檚 people working long hours or doing things they can鈥檛 do all the time.鈥�

The world and its celestial surroundings are diverse, meaning there is plenty of room for researchers like Wilson to leave a mark. His experience inside the HERA facility holds one of the keys to unlocking that potential.

鈥淪pace is a really interesting thing because humans are not designed to be there. We don鈥檛 even fully understand cognition on Earth,鈥� said Wilson. 鈥淚f we can find an effective way to monitor that experience then we can figure out a way to improve it, as well. But we have to get data first.鈥�

Robert Wilson (PhDMechEngr'20) spent 45 days locked inside NASA鈥檚 HERA facility, a high-tech simulation designed to test the limits of human endurance in deep space. His mission could help shape the future of space exploration鈥攁nd life back on Earth.

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From research to impact: Massimo Ruzzene

Alexander James Servantez — Mon, 31 Mar 2025 15:52:12 +0000

From research to impact: Massimo Ruzzene Alexander Jame鈥� Mon, 03/31/2025 - 09:52

Professor Massimo Ruzzene is the senior vice chancellor for research and innovation. His goal is to foster a campus environment that turns research into real-world impact in areas such as quantum, space, climate and health.

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Sustainable Spinouts: Innovation in Action

Alexander James Servantez — Fri, 21 Mar 2025 17:22:08 +0000

Sustainable Spinouts: Innovation in Action Alexander Jame鈥� Fri, 03/21/2025 - 11:22

CU Boulder is a hub for sustainable entrepreneurship. Spinouts such as Associate Professor Greg Rieker's LongPath Technologies, Professor Se-Hee Lee's Solid Power and Associate Professor Chunmei Ban's Mana Battery are just some of the university's latest successful ventures motivated by protecting the environment.

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CU Boulder startup Mesa Quantum earns two major grants to improve navigation infrastructure

Alexander James Servantez — Fri, 21 Mar 2025 16:45:19 +0000

CU Boulder startup Mesa Quantum earns two major grants to improve navigation infrastructure Alexander Jame鈥� Fri, 03/21/2025 - 10:45

For over 20 years, Associate Research Professor Svenja Knappe has focused on developing miniaturized quantum sensors and systems. Now the technology is helping CU Boulder spinout Mesa Quantum commercialize chip-scale quantum solutions that can transform our navigation infrastructure.

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People of color breathe Denver鈥檚 smelliest air

Alexander James Servantez — Mon, 17 Mar 2025 21:17:27 +0000

People of color breathe Denver鈥檚 smelliest air Alexander Jame鈥� Mon, 03/17/2025 - 15:17

A new CU Boulder-led study, headlined by Professor Shelly Miller, shows that Denver residents in marginalized areas of the city are more likely to be exposed to odor emitting facilities. However, these communities are also the least likely to report these odors to the city, a statistic that Miller and her colleagues would like to see change.

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Wiedinmyer on the power, importance of NOAA weather forecasting

Alexander James Servantez — Mon, 10 Mar 2025 16:16:26 +0000

Wiedinmyer on the power, importance of NOAA weather forecasting Alexander Jame鈥� Mon, 03/10/2025 - 10:16

Research Professor Christine Wiedinmyer is an atmospheric expert whose research investigates the impact of air pollutants on air quality, climate and public health. In this article by The Conversation, Wiedinmyer gives a behind-the-scenes look at how NOAA forecasters use technology to predict the weather, and how important they are to the fabric of our everyday life.

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Robotic bees? These bio-inspired robots redefine the boundaries of autonomy and sustainability

Matthew Cumpton — Wed, 05 Mar 2025 22:00:00 +0000

Robotic bees? These bio-inspired robots redefine the boundaries of autonomy and sustainability Matthew Cumpton Wed, 03/05/2025 - 15:00

Madison Seckman

With rapid advancements in robotics and AI, the line between science fiction and reality continues to blur. At the heart of this innovation lies a breakthrough: drones designed to solve pressing global challenges, from pollinating crops to navigating wildfire zones.

This vision drives Assistant Professor Chahat Singh, leader of the PRAISe (Perception, Robotics, AI and Sensing) Lab in the Paul M. Rady Department of Mechanical Engineering. With an academic background spanning electronics, robotics, and computer science, Singh is dedicated to exploring the frontiers of bio-inspired robotics and AI in resource-constrained systems.

Assistant Professor Chahat Singh next to one of his compact and autonomous robotic designs.

Singh鈥檚 overarching research question is deceptively simple: What is the minimum amount of computational power, sensor capability, and resources required for small robots to achieve autonomy? This challenge is compounded by the scale of the robots he designs, which are constrained by limited computational capacity and lightweight requirements. They are two to three inches in length and orders of magnitude smaller in terms of physical size and computational power than traditional robots. 鈥淲e鈥檙e working with systems that have 100 times less computing power than a Boston Dynamics鈥� Spot robot,鈥� Singh explained. 鈥淭he goal is to achieve autonomy with the bare minimum.鈥�

One of Singh鈥檚 most notable projects focuses on autonomous drones for pollination, inspired by the overwhelming loss of honeybee colonies. 鈥淭he question was whether today鈥檚 robotics and AI could fill this gap until we have a more sustainable biological solution,鈥� Singh said. The answer lies in his innovative, lightweight drones that can navigate autonomously through forests and fields without relying on external communication or GPS, making them secure and efficient.

Singh鈥檚 current drone model incorporates multiple onboard cameras, which enables it to identify and align with flowers for pollination. The cameras use advanced neural depth-perception algorithms powered by AI-accelerated computers. Many creatures have developed different pupil shapes based on their habitats which allow variations in incoming light and amount of blur to help them determine the depth of objects. 鈥淭he cameras are inspired by biological systems,鈥� he explained.

Singh showcasing the small scale of materials in his robot's design. His goal is to develop autonomous drones with less resources and power than traditional robots.

Singh鈥檚 drones are not just technologically advanced鈥攖hey鈥檙e engineering marvels. Built from carbon fiber frames, these drones are lightweight yet robust, weighing around 250 grams. They use lithium ion batteries which are heavy and tend to die quickly, so he has started to look at ways to charge the batteries while the robots are outside.

To overcome these limitations, Singh has developed a 鈥渕other drone鈥� system. The larger drone carries smaller drones to the target area and acts as a mobile charging station. Once deployed, the smaller drones autonomously search for flowers and begin pollination. This approach not only extends operational time but also reduces the energy expenditure of individual drones. 鈥淚t鈥檚 a highly efficient system that mirrors natural ecosystems,鈥� Singh said.

While the pollination drones have gathered attention, Singh鈥檚 research has broader implications. His team is working on compressing advanced AI models, such as language and vision models, to operate on resource-constrained systems. 鈥淚magine a robot navigating a forest during a wildfire,鈥� Singh said. 鈥淚t needs to make decisions on the spot, without internet access or pre-programmed instructions. That鈥檚 the next frontier鈥攅mbedding foundational AI models into small, autonomous robots.鈥�

Singh鈥檚 vision extends to deploying fleets of robots for tasks like firefighting, disaster response, and ecological monitoring. By creating swarms of cost-effective, autonomous robots, he aims to revolutionize industries that rely on expensive, large-scale systems. 鈥淪maller robots are not just cool鈥攖hey鈥檙e necessary,鈥� he emphasized. 鈥淭hey offer safety, robustness, and cost-effectiveness.鈥�

Despite the groundbreaking nature of his work, he is committed to open-source principles. 鈥淚 believe in openness because this research is for the greater good,鈥� he said. Singh has already shared software for drone operation and plans to release additional resources to empower other researchers and innovators.

When asked about his favorite part of the research, Singh highlighted the hope it brings for the future. 鈥淲hether it鈥檚 addressing ecological crises or enhancing technology, I want to create robot systems that are safe, innovative and sustainable,鈥� he said. 鈥淭his is about pushing the boundaries of what鈥檚 possible while respecting the natural world.鈥�

Assistant Professor Chahat Singh is pioneering advancements in bio-inspired robotics and resource-constrained AI. His work focuses on developing small, autonomous drones capable of solving global challenges, such as pollinating crops and navigating wildfire zones.

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Meet 5 types of robots with living body parts

Alexander James Servantez — Mon, 03 Mar 2025 19:09:09 +0000

Meet 5 types of robots with living body parts Alexander Jame鈥� Mon, 03/03/2025 - 12:09

Living organisms have evolved across the span of millions of years to do things that are nearly impossible even for today's machines. But what happens when you combine biology and engineering to create more capable robots? Assistant Professor Nicole Xu shares her lab's efforts to create the next generation of cyborg jellyfish explorers.

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Tiny insects could lead to big changes in robot design

Alexander James Servantez — Mon, 24 Feb 2025 18:47:32 +0000

Tiny insects could lead to big changes in robot design Alexander Jame鈥� Mon, 02/24/2025 - 11:47

Professor Sean Humbert is being awarded a five-year, $909,000 grant to make robotic advancements in flight physics and aerial systems. How? By unlocking the biological secrets of your common, everyday housefly.

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