Hamsa Balakrishnan appointed associate dean of engineering

Hamsa Balakrishnan, the William E. Leonhard (1940) Professor in the Department of Aeronautics and Astronautics (AeroAstro) at MIT, has been appointed associate dean of the MIT School of Engineering effective Aug. 1.

As associate dean, Balakrishnan will focus on efforts to attract, retain, and support top talent across all academic levels in the School of Engineering. She will help lead and shape various faculty-focused programs and will help manage many of the school’s student-facing programs and initiatives. Balakrishnan will also support both faculty and students across the school with regards to fellowships, awards, and honors. Additionally, she will support and contribute to a number of key groups within the school.

“Professor Balakrishnan’s passion and dedication have already made a lasting impact on the School of Engineering. Through leadership roles in AeroAstro and beyond, she has demonstrated a commitment to supporting and uplifting our students, faculty, and staff. I am delighted to welcome her to the School of Engineering faculty leadership team,” says Anantha Chandrakasan, chief innovation and strategy officer, dean of the School of Engineering, and the Vannevar Bush Professor of Electrical Engineering and Computer Science.

As principal investigator of the Dynamics, Infrastructure Networks, and Mobility (DINaMo) group, Balakrishnan and her team research the modeling, analysis, control, and optimization of modern infrastructure systems. They have collaborated with the U.S. Federal Aviation Administration, NASA, and major airports to address challenges such as advanced air mobility, air traffic congestion, and airport operations.

Balakrishnan served as associate department head in AeroAstro from 2018 to 2021. In that role, she was responsible for the undergraduate and graduate education programs in the department. During her tenure as associate department head, she restructured graduate student recruiting through the use of multi-year fellowships, coordinated the mid-semester shift to remote instruction in March 2020, and introduced a first-of-its-kind provisional funding program for PhD students who wished to change research groups.

Balakrishnan also served as director of Transportation@MIT in 2018-19. During this time, she managed the interdepartmental graduate programs in transportation that span the schools of Engineering and Architecture and Planning, focusing on improving faculty engagement and student recruiting to the program.

In addition to her roles at MIT, Balakrishnan co-founded Lumo, which uses data and analytics to predict flight delays. She currently serves as the company’s chief scientist.

Over the course of her career, Balakrishnan has received numerous honors and accolades for both her research contributions and her dedication as an educator. In addition to being named an associate fellow of the American Institute of Aeronautics and Astronautics (AIAA), she has been honored with an NSF CAREER Award, the inaugural CNA Award for Operational Analysis, AIAA’s Lawrence Sperry Award, and the American Automatic Control Council’s Donald P. Eckman Award. She has also been recognized for her mentorship and support of students with a Committed to Caring Award, the MIT AIAA Undergraduate Teaching Award, and the MIT AIAA Undergraduate Advising Award.

Balakrishnan received her bachelor’s degree from the Indian Institute of Technology at Madras, and her master’s and doctoral degrees from Stanford University. Before joining MIT, she served as a principal development engineer at the University Affiliated Research Center at the University of California Santa Cruz and NASA Ames Research Center's Terminal Air Traffic Management Concepts Branch.

Balakrishnan succeeds Elsa Olivetti, the Jerry McAfee Professor in Engineering in the Department of Materials Science and Engineering, who has served as associate dean of engineering since Sept. 1, 2023 and was recently named an MIT Climate Project mission director. Olivetti will continue in her role as associate dean until the end of August.

“I’m grateful to Professor Olivetti for her tremendous dedication to the School of Engineering. Her contributions to the school’s leadership team were substantial. I’m thrilled that the MIT Climate Project will benefit from her passion and expertise,” adds Chandrakasan. 

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MIT School of Science launches Center for Sustainability Science and Strategy

The MIT School of Science is launching a center to advance knowledge and computational capabilities in the field of sustainability science, and support decision-makers in government, industry, and civil society to achieve sustainable development goals. Aligned with the Climate Project at MIT, researchers at the MIT Center for Sustainability Science and Strategy will develop and apply expertise from across the Institute to improve understanding of sustainability challenges, and thereby provide actionable knowledge and insight to inform strategies for improving human well-being for current and future generations.

Noelle Selin, professor at MIT’s Institute for Data, Systems and Society and the Department of Earth, Atmospheric and Planetary Sciences, will serve as the center’s inaugural faculty director. C. Adam Schlosser and Sergey Paltsev, senior research scientists at MIT, will serve as deputy directors, with Anne Slinn as executive director.

Incorporating and succeeding both the Center for Global Change Science and Joint Program on the Science and Policy of Global Change while adding new capabilities, the center aims to produce leading-edge research to help guide societal transitions toward a more sustainable future. Drawing on the long history of MIT’s efforts to address global change and its integrated environmental and human dimensions, the center is well-positioned to lead burgeoning global efforts to advance the field of sustainability science, which seeks to understand nature-society systems in their full complexity. This understanding is designed to be relevant and actionable for decision-makers in government, industry, and civil society in their efforts to develop viable pathways to improve quality of life for multiple stakeholders.

“As critical challenges such as climate, health, energy, and food security increasingly affect people’s lives around the world, decision-makers need a better understanding of the earth in its full complexity — and that includes people, technologies, and institutions as well as environmental processes,” says Selin. “Better knowledge of these systems and how they interact can lead to more effective strategies that avoid unintended consequences and ensure an improved quality of life for all.”    

Advancing knowledge, computational capability, and decision support

To produce more precise and comprehensive knowledge of sustainability challenges and guide decision-makers to formulate more effective strategies, the center has set the following goals:

• Advance fundamental understanding of the complex interconnected physical and socio-economic systems that affect human well-being. As new policies and technologies are developed amid climate and other global changes, they interact with environmental processes and institutions in ways that can alter the earth’s critical life-support systems. Fundamental mechanisms that determine many of these systems’ behaviors, including those related to interacting climate, water, food, and socio-economic systems, remain largely unknown and poorly quantified. Better understanding can help society mitigate the risks of abrupt changes and “tipping points” in these systems.
• Develop, establish and disseminate new computational tools toward better understanding earth systems, including both environmental and human dimensions. The center’s work will integrate modeling and data analysis across disciplines in an era of increasing volumes of observational data. MIT multi-system models and data products will provide robust information to inform decision-making and shape the next generation of sustainability science and strategy.
• Produce actionable science that supports equity and justice within and across generations. The center’s research will be designed to inform action associated with measurable outcomes aligned with supporting human well-being across generations. This requires engaging a broad range of stakeholders, including not only nations and companies, but also nongovernmental organizations and communities that take action to promote sustainable development — with special attention to those who have historically borne the brunt of environmental injustice.

“The center’s work will advance fundamental understanding in sustainability science, leverage leading-edge computing and data, and promote engagement and impact,” says Selin. “Our researchers will help lead scientists and strategists across the globe who share MIT’s commitment to mobilizing knowledge to inform action toward a more sustainable world.”

Building a better world at MIT

Building on existing MIT capabilities in sustainability, science, and strategy, the center aims to: 

• focus research, education, and outreach under a theme that reflects a comprehensive state of the field and international research directions, fostering a dynamic community of students, researchers, and faculty;
• raise the visibility of sustainability science at MIT, emphasizing links between science and action, in the context of existing Institute goals and other efforts on climate and sustainability, and in a way that reflects the vital contributions of a range of natural and social science disciplines to understanding human-environment systems; and
• re-emphasize MIT’s long-standing expertise in integrated systems modeling while leveraging the Institute’s concurrent leading-edge strengths in data and computing, establishing leadership that harnesses recent innovations, including those in machine learning and artificial intelligence, toward addressing the science challenges of global change and sustainability.

“The Center for Sustainability Science and Strategy will provide the necessary synergy for our MIT researchers to develop, deploy, and scale up serious solutions to climate change and other critical sustainability challenges,” says Nergis Mavalvala the Curtis and Kathleen Marble Professor of Astrophysics and dean of the MIT School of Science. “With Professor Selin at its helm, the center will also ensure that these solutions are created in concert with the people who are directly affected now and in the future.”

The center builds on more than three decades of achievements by the Center for Global Change Science and the Joint Program on the Science and Policy of Global Change, both of which were directed or co-directed by professor of atmospheric science Ronald Prinn.

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Empowering the next generation of scientists in Africa

No one is born a world-class scientist. Instead, their skills are built over many years of education, networking, mentorship, and work in laboratories or in the field.

That’s the fundamental insight behind the not-for-profit organization Future African Scientist, which is seeking to unleash the scientific potential of the continent by providing African students and early-career scientists with the support they need to do world-renowned research that addresses problems in their local communities and beyond.

Future African Scientist, or FAS, partners with leading scientists and institutions around the world, including MIT, to offer educational courses, training, networking events, and other programming around scientific research and entrepreneurship. More importantly, graduates of FAS programs join a network of scientists that helps them match with jobs, internships, and further learning opportunities.

“Our programs aim to democratize access to science education and create a new wave of scientists that are going to study African problems and not just publish papers, but also translate that research into beneficial products as well as policies,” says FAS co-founder Martin Lubowa.

At the core of FAS is a belief in the power of connections to further scientific understanding. Perhaps it’s no surprise, then, that FAS began with a connection between two people from very different walks of life during an MIT program.

From roommates to co-founders

In 2020, Daniel Zhang ’22 participated in Biology Professor Bruce Walker’s course HST. 434 (Evolution of an Epidemic) as part of a MISTI Global Classroom during MIT’s Independent Activities Period (IAP). The course immerses students in a South African community to teach them about the AIDS epidemic from the perspective of doctors, researchers, policymakers, and local infected women.

That IAP happened to be the first year the class paired MIT students with students from the African Leadership Academy, which seeks to build leadership skills in African youth. Zhang’s roommate was Martin Lubowa.

“Martin and I bonded instantly despite coming from completely different cultures and backgrounds,” Zhang recalls. “We shared passions for education, mentorship, and sports.”

Despite waking up early each day for class, Zhang and Lubowa talked late into the nights. Many of their conversations centered around the differences in STEM opportunities between students in the U.S. and African countries. They also discussed the importance of STEM in economic development and eventually identified a lack of mentorship programs as a key problem. They decided to found Future African Scientist to close those gaps.

With support and encouragement from Walker, the pair kept in touch after the class and focused their mission to equipping university and high school students in Africa with early-stage mentorship and critical thinking skills that would enable them to conduct independent research projects.

In January 2022, they organized their first virtual bootcamp for students across Africa. The bootcamp featured virtual courses, lectures by leading African scientists, mentorship opportunities, and a capstone project that challenged students to apply their learnings.

“We didn’t want to just give them research skills, but also entrepreneurship skills and interpersonal skills to position them as scientific entrepreneurs,” Lubowa says.

After receiving positive feedback and learning more about the skills students needed, the founders broadened the structure of FAS.

Today, a similar bootcamp on foundational research skills serves as the first stage of FAS’s four-part Africa Science Research Academy. The second stage is a data-driven research project that exposes participants to working in a lab. The third stage teaches skills including entrepreneurship, leadership, financial literacy, and grant management. The final stage, the Africa Science Opportunity Network, is available to FAS graduates for life and is designed to connect participants with internships, jobs opportunities, and other research projects.

“What makes us different from most of the research training programs in Africa is that we are open to anyone who is curious,” Lubowa says. “Most of the programs on the continent target MDs who already practicing, or PhDs, which is a bit unfair for people who are curious, but they don’t have the right platform to channel that curiosity into meaningful experiences.”

To date, more than 100 students and young professionals have gone through FAS programming. The students hail from more than 30 universities and 15 countries. FAS has also partnered with 10 medical student associations that have helped it expand its network to more than 100,000 students across the continent. FAS is also in conversations with organizations like the African Microscope Initiative, which has offered to recruit FAS graduates for more specialized training in bioimaging, as well as African state governments to create upskilling programs that could serve as alternatives to MD and PhD programs.

“We see Africa transitioning from just being a beneficiary of the global scientific community to becoming a contributor,” Lubowa says. “That means we can help the U.S. and other Western countries solve their problems. The issue at the moment is getting people the skills they need and changing their mindset so they understand they can do great things, and that in the long run, they can not just generate knowledge, but also create enterprises that address some of these challenges within Africa and beyond.”

Meeting the needs of the continent

In 2022, a pair of students from the Association of Mbarara University Pharmaceutical Sciences in Uganda learned about the foundations of entrepreneurship through FAS’ programming. They are in the process of commercializing their research into mosquito repellants made from locally-sourced materials. That same year, an undergraduate Cameroonian alumna of FAS placed third in a national science competition despite going up against PhDs. His research was in early detection of pancreatic cancer.

“One of the aspirational goals of Future African Scientists is to cultivate a sustainable scientific ecosystem where beyond academia, there’s also a science industry in Africa,” Lubowa says.

Further down the line, FAS would like to open its own laboratories to broaden access to equipment, and FAS’s team has already spoken with companies that exchange second-hand medical and laboratory equipment to help improve scientific infrastructure at African institutes.

“Our long-term plans include establishing general-purpose, open laboratories where students across Africa can go and learn how to do practical science,” Lubowa says.

With all work, FAS seeks to empower Africans to become a global scientific force for good.

“We have a population of 1.2 billion people in Africa, but we only have 198 scientists per million people. The U.S. has more than 4,000 scientists per million people,” Lubowa says. “Africans also have the highest burden of disease, so there’s really a need for us to rethink how we have been training scientists, and it all goes back to these support systems. I really think we can change the scientific landscape in Africa.”

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Scientists pin down the origins of the moon’s tenuous atmosphere

While the moon lacks any breathable air, it does host a barely-there atmosphere. Since the 1980s, astronomers have observed a very thin layer of atoms bouncing over the moon’s surface. This delicate atmosphere — technically known as an “exosphere” — is likely a product of some kind of space weathering. But exactly what those processes might be has been difficult to pin down with any certainty.

Now, scientists at MIT and the University of Chicago say they have identified the main process that formed the moon’s atmosphere and continues to sustain it today. In a study appearing today in Science Advances, the team reports that the lunar atmosphere is primarily a product of “impact vaporization.”

In their study, the researchers analyzed samples of lunar soil collected by astronauts during NASA’s Apollo missions. Their analysis suggests that over the moon’s 4.5-billion-year history its surface has been continuously bombarded, first by massive meteorites, then more recently, by smaller, dust-sized “micrometeoroids.” These constant impacts have kicked up the lunar soil, vaporizing certain atoms on contact and lofting the particles into the air. Some atoms are ejected into space, while others remain suspended over the moon, forming a tenuous atmosphere that is constantly replenished as meteorites continue to pelt the surface.

The researchers found that impact vaporization is the main process by which the moon has generated and sustained its extremely thin atmosphere over billions of years.

“We give a definitive answer that meteorite impact vaporization is the dominant process that creates the lunar atmosphere,” says the study’s lead author, Nicole Nie, an assistant professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “The moon is close to 4.5 billion years old, and through that time the surface has been continuously bombarded by meteorites. We show that eventually, a thin atmosphere reaches a steady state because it’s being continuously replenished by small impacts all over the moon.”

Nie’s co-authors are Nicolas Dauphas, Zhe Zhang, and Timo Hopp at the University of Chicago, and Menelaos Sarantos at NASA Goddard Space Flight Center.

Weathering’s roles

In 2013, NASA sent an orbiter around the moon to do some detailed atmospheric reconnaissance. The Lunar Atmosphere and Dust Environment Explorer (LADEE, pronounced “laddie”) was tasked with remotely gathering information about the moon’s thin atmosphere, surface conditions, and any environmental influences on the lunar dust.

LADEE’s mission was designed to determine the origins of the moon’s atmosphere. Scientists hoped that the probe’s remote measurements of soil and atmospheric composition might correlate with certain space weathering processes that could then explain how the moon’s atmosphere came to be.

Researchers suspect that two space weathering processes play a role in shaping the lunar atmosphere: impact vaporization and “ion sputtering” — a phenomenon involving solar wind, which carries energetic charged particles from the sun through space. When these particles hit the moon’s surface, they can transfer their energy to the atoms in the soil and send those atoms sputtering and flying into the air. 

“Based on LADEE’s data, it seemed both processes are playing a role,” Nie says. “For instance, it showed that during meteorite showers, you see more atoms in the atmosphere, meaning impacts have an effect. But it also showed that when the moon is shielded from the sun, such as during an eclipse, there are also changes in the atmosphere’s atoms, meaning the sun also has an impact. So, the results were not clear or quantitative.”

Answers in the soil

To more precisely pin down the lunar atmosphere’s origins, Nie looked to samples of lunar soil collected by astronauts throughout NASA’s Apollo missions. She and her colleagues at the University of Chicago acquired 10 samples of lunar soil, each measuring about 100 milligrams — a tiny amount that she estimates would fit into a single raindrop.

Nie sought to first isolate two elements from each sample: potassium and rubidium. Both elements are “volatile,” meaning that they are easily vaporized by impacts and ion sputtering. Each element exists in the form of several isotopes. An isotope is a variation of the same element, that consists of the same number of protons but a slightly different number of neutrons. For instance, potassium can exist as one of three isotopes, each one having one more neutron, and there being slightly heavier than the last. Similarly, there are two isotopes of rubidium.

The team reasoned that if the moon’s atmosphere consists of atoms that have been vaporized and suspended in the air, lighter isotopes of those atoms should be more easily lofted, while heavier isotopes would be more likely to settle back in the soil. Furthermore, scientists predict that impact vaporization, and ion sputtering, should result in very different isotopic proportions in the soil. The specific ratio of light to heavy isotopes that remain in the soil, for both potassium and rubidium, should then reveal the main process contributing to the lunar atmosphere’s origins.

With all that in mind, Nie analyzed the Apollo samples by first crushing the soils into a fine powder, then dissolving the powders in acids to purify and isolate solutions containing potassium and rubidium. She then passed these solutions through a mass spectrometer to measure the various isotopes of both potassium and rubidium in each sample.

In the end, the team found that the soils contained mostly heavy isotopes of both potassium and rubidium. The researchers were able to quantify the ratio of heavy to light isotopes of both potassium and rubidium, and by comparing both elements, they found that impact vaporization was most likely the dominant process by which atoms are vaporized and lofted to form the moon’s atmosphere.

“With impact vaporization, most of the atoms would stay in the lunar atmosphere, whereas with ion sputtering, a lot of atoms would be ejected into space,” Nie says. “From our study, we now can quantify the role of both processes, to say that the relative contribution of impact vaporization versus ion sputtering is about 70:30 or larger.” In other words, 70 percent or more of the moon’s atmosphere is a product of meteorite impacts, whereas the remaining 30 percent is a consequence of the solar wind.

“The discovery of such a subtle effect is remarkable, thanks to the innovative idea of combining potassium and rubidium isotope measurements along with careful, quantitative modeling,” says Justin Hu, a postdoc who studies lunar soils at Cambridge University, who was not involved in the study. “This discovery goes beyond understanding the moon’s history, as such processes could occur and might be more significant on other moons and asteroids, which are the focus of many planned return missions.”

“Without these Apollo samples, we would not be able to get precise data and measure quantitatively to understand things in more detail,” Nie says. “It’s important for us to bring samples back from the moon and other planetary bodies, so we can draw clearer pictures of the solar system’s formation and evolution.”

This work was supported, in part, by NASA and the National Science Foundation.

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Scientists find a human “fingerprint” in the upper troposphere’s increasing ozone

Ozone can be an agent of good or harm, depending on where you find it in the atmosphere. Way up in the stratosphere, the colorless gas shields the Earth from the sun’s harsh ultraviolet rays. But closer to the ground, ozone is a harmful air pollutant that can trigger chronic health problems including chest pain, difficulty breathing, and impaired lung function.

And somewhere in between, in the upper troposphere — the layer of the atmosphere just below the stratosphere, where most aircraft cruise — ozone contributes to warming the planet as a potent greenhouse gas.

There are signs that ozone is continuing to rise in the upper troposphere despite efforts to reduce its sources at the surface in many nations. Now, MIT scientists confirm that much of ozone’s increase in the upper troposphere is likely due to humans.

In a paper appearing today in the journal Environmental Science and Technology, the team reports that they detected a clear signal of human influence on upper tropospheric ozone trends in a 17-year satellite record starting in 2005.

“We confirm that there’s a clear and increasing trend in upper tropospheric ozone in the northern midlatitudes due to human beings rather than climate noise,” says study lead author Xinyuan Yu, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS).

“Now we can do more detective work and try to understand what specific human activities are leading to this ozone trend,” adds co-author Arlene Fiore, the Peter H. Stone and Paola Malanotte Stone Professor in Earth, Atmospheric and Planetary Sciences.

The study’s MIT authors include Sebastian Eastham and Qindan Zhu, along with Benjamin Santer at the University of California at Los Angeles, Gustavo Correa of Columbia University, Jean-François Lamarque at the National Center for Atmospheric Research, and Jerald Zimeke at NASA Goddard Space Flight Center.

Ozone’s tangled web

Understanding ozone’s causes and influences is a challenging exercise. Ozone is not emitted directly, but instead is a product of “precursors” — starting ingredients, such as nitrogen oxides and volatile organic compounds (VOCs), that react in the presence of sunlight to form ozone. These precursors are generated from vehicle exhaust, power plants, chemical solvents, industrial processes, aircraft emissions, and other human-induced activities.

Whether and how long ozone lingers in the atmosphere depends on a tangle of variables, including the type and extent of human activities in a given area, as well as natural climate variability. For instance, a strong El Niño year could nudge the atmosphere’s circulation in a way that affects ozone’s concentrations, regardless of how much ozone humans are contributing to the atmosphere that year.

Disentangling the human- versus climate-driven causes of ozone trend, particularly in the upper troposphere, is especially tricky. Complicating matters is the fact that in the lower troposphere — the lowest layer of the atmosphere, closest to ground level — ozone has stopped rising, and has even fallen in some regions at northern midlatitudes in the last few decades. This decrease in lower tropospheric ozone is mainly a result of efforts in North America and Europe to reduce industrial sources of air pollution.

“Near the surface, ozone has been observed to decrease in some regions, and its variations are more closely linked to human emissions,” Yu notes. “In the upper troposphere, the ozone trends are less well-monitored but seem to decouple with those near the surface, and ozone is more easily influenced by climate variability. So, we don’t know whether and how much of that increase in observed ozone in the upper troposphere is attributed to humans.”

A human signal amid climate noise

Yu and Fiore wondered whether a human “fingerprint” in ozone levels, caused directly by human activities, could be strong enough to be detectable in satellite observations in the upper troposphere. To see such a signal, the researchers would first have to know what to look for.

For this, they looked to simulations of the Earth’s climate and atmospheric chemistry. Following approaches developed in climate science, they reasoned that if they could simulate a number of possible climate variations in recent decades, all with identical human-derived sources of ozone precursor emissions, but each starting with a slightly different climate condition, then any differences among these scenarios should be due to climate noise. By inference, any common signal that emerged when averaging over the simulated scenarios should be due to human-driven causes. Such a signal, then, would be a “fingerprint” revealing human-caused ozone, which the team could look for in actual satellite observations.

With this strategy in mind, the team ran simulations using a state-of-the-art chemistry climate model. They ran multiple climate scenarios, each starting from the year 1950 and running through 2014.

From their simulations, the team saw a clear and common signal across scenarios, which they identified as a human fingerprint. They then looked to tropospheric ozone products derived from multiple instruments aboard NASA’s Aura satellite.

“Quite honestly, I thought the satellite data were just going to be too noisy,” Fiore admits. “I didn’t expect that the pattern would be robust enough.”

But the satellite observations they used gave them a good enough shot. The team looked through the upper tropospheric ozone data derived from the satellite products, from the years 2005 to 2021, and found that, indeed, they could see the signal of human-caused ozone that their simulations predicted. The signal is especially pronounced over Asia, where industrial activity has risen significantly in recent decades and where abundant sunlight and frequent weather events loft pollution, including ozone and its precursors, to the upper troposphere.

Yu and Fiore are now looking to identify the specific human activities that are leading to ozone’s increase in the upper troposphere.

“Where is this increasing trend coming from? Is it the near-surface emissions from combusting fossil fuels in vehicle engines and power plants? Is it the aircraft that are flying in the upper troposphere? Is it the influence of wildland fires? Or some combination of all of the above?” Fiore says. “Being able to separate human-caused impacts from natural climate variations can help to inform strategies to address climate change and air pollution.”

This research was funded, in part, by NASA.

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From large labs to small teams, mentorship thrives

Each year, new MIT graduate students are tasked with the momentous decision of choosing a research group that will serve as their home for the next several years. Among many questions they face: join an established research effort, or work with a new faculty member in a growing group?

Professors Cynthia Breazeal, leading a group of over 30 students, and Ming Guo, with a lab of fewer than 10, demonstrate that excellent mentorship can thrive in a research group of any size.

Cynthia Breazeal: Flexible leadership

Cynthia Breazeal is a professor of media arts and sciences at MIT, where she founded and directs the Personal Robots group at the MIT Media Lab. She is also the MIT dean for digital learning, leading MIT Open Learning’s business and research and engagement units. Breazeal is a pioneer of social robotics and human-robot interaction, and her research group investigates social robots applied to education, pediatrics, health and wellness, and aging.

Breazeal’s focus on taking multidisciplinary approaches to her research has resulted in an inclusive and supportive lab environment. Moreover, she does not shy away from taking students with unconventional backgrounds.

One nominator joined Breazeal's lab as a design researcher without a computer science background. However, Breazeal recognized the value of their work within the context of her lab’s research directions. “I was a bit of an oddball in the group”, the nominator modestly recounts, “but had joined to help make the work in the group more human-centered.”

Throughout the student's academic journey, Breazeal offered unwavering support, whether by connecting them with experts to solve specific problems or guiding them through the academic job search process.

Over the Covid-19 pandemic, Breazeal prioritized gathering student feedback through a survey about how she could best support her research group. In response to this input, Breazeal established the Senior Research Team (SRT) within her group.

The SRT includes PhD holders such as postdocs and research scientists who provide personalized mentorship to one or two graduate students per semester. The SRT members serve as dedicated advocates and points of contact, with weekly check-ins to address questions within the lab. Additionally, SRT members meet by themselves weekly to discuss student concerns and bring up urgent issues with Breazeal directly. Lastly, students can sign up for meetings with Breazeal and participate in paper review sessions with her and co-authors.

In the nominator’s opinion, this new system was implemented because Breazeal cares about her students and her lab culture. With over 30 members in her group, Breazeal cannot provide hands-on support for everyone daily, but she still deeply cares about each person's experience in the lab. The nominator shared that Breazeal “understands as she progresses in her career, she needs to make sure that she is changing and creating new systems for her research group to continue to operate smoothly.”

Ming Guo: Emphasizing learning over achievement

Ming Guo is an associate professor in the Department of Mechanical Engineering. Guo’s group works at the interface of mechanics, physics, and cell biology, seeking to understand how physical properties and biological function affect each other in cellular systems.

A key aspect of Guo’s mentorship style is his ability to foster an environment where students feel comfortable expressing their difficulties. He actively shows empathy for his students’ lives outside of the lab, often reaching out to provide support during challenging times. When one nominator found themselves faced with significant personal difficulties, Guo made a point to check in regularly, ensuring the student had a support network of friends and labmates.

Guo champions his students both academically and personally. For instance, when a collaborating lab placed unrealistic expectations on a student’s experimental output, Guo openly praised the student’s efforts and achievements in a joint meeting, alleviating pressure and highlighting the student’s hard work.

In addition, Guo encourages vulnerable conversations about issues affecting students, such as political developments and racial inequities. During the graduate student unionization process, he fostered open discussion, showing genuine interest in understanding the challenges faced by graduate students and using these insights to better support them.

In Guo’s research group, learning and development are prioritized over achievements and goals. When students encounter challenges in their research, Guo helps them maintain perspective by validating their struggles and recognizing the skills they acquire through difficult experiments. By celebrating their progress and emphasizing the importance of the learning process, he ensures that students understand the value of their experiences beyond outcomes. This approach not only boosts their confidence, but also fosters a deeper appreciation for the scientific process and their own development as researchers.

Guo says that he feels most energized and happy when he talks to students. He looks forward to the new ideas that they present. One nominator commented on how much Guo enjoys giving feedback at group meetings: “Sometimes he isn’t convinced in the beginning, but he has cultivated our lab atmosphere to be conducive to extended discussion.”

The nominator continues, “When things do work and become really interesting, he is extremely excited with us and pushes us to share our own ideas with the wider research community.” 

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Physicists report new insights into exotic particles key to magnetism

MIT physicists and colleagues report new insights into exotic particles key to a form of magnetism that has attracted growing interest because it originates from ultrathin materials only a few atomic layers thick. The work, which could impact future electronics and more, also establishes a new way to study these particles through a powerful instrument at the National Synchrotron Light Source II at Brookhaven National Laboratory.

Among their discoveries, the team has identified the microscopic origin of these particles, known as excitons. They showed how they can be controlled by chemically “tuning” the material, which is primarily composed of nickel. Further, they found that the excitons propagate throughout the bulk material instead of being bound to the nickel atoms.

Finally, they proved that the mechanism behind these discoveries is ubiquitous to similar nickel-based materials, opening the door for identifying — and controlling — new materials with special electronic and magnetic properties.

The open-access results are reported in the July 12 issue of Physical Review X.

“We’ve essentially developed a new research direction into the study of these magnetic two-dimensional materials that very much relies on an advanced spectroscopic method, resonant inelastic X-ray scattering (RIXS), which is available at Brookhaven National Lab,” says Riccardo Comin, MIT’s Class of 1947 Career Development Associate Professor of Physics and leader of the work. Comin is also affiliated with the Materials Research Laboratory and the Research Laboratory of Electronics.

Comin’s colleagues on the work include Connor A. Occhialini, an MIT graduate student in physics, and Yi Tseng, a recent MIT postdoc now at Deutsches Elektronen-Synchrotron (DESY). The two are co-first authors of the Physical Review X paper.

Additional authors are Hebatalla Elnaggar of the Sorbonne; Qian Song, a graduate student in MIT’s Department of Physics; Mark Blei and Seth Ariel Tongay of Arizona State University; Frank M. F. de Groot of Utrecht University; and Valentina Bisogni and Jonathan Pelliciari of Brookhaven National Laboratory.

Ultrathin layers

The magnetic materials at the heart of the current work are known as nickel dihalides. They are composed of layers of nickel atoms sandwiched between layers of halogen atoms (halogens are one family of elements), which can be isolated to atomically thin layers. In this case, the physicists studied the electronic properties of three different materials composed of nickel and the halogens chlorine, bromine, or iodine. Despite their deceptively simple structure, these materials host a rich variety of magnetic phenomena.

The team was interested in how these materials’ magnetic properties respond when exposed to light. They were specifically interested in particular particles — the excitons — and how they are related to the underlying magnetism. How exactly do they form? Can they be controlled?

Enter excitons

A solid material is composed of different types of elementary particles, such as protons and electrons. Also ubiquitous in such materials are “quasiparticles” that the public is less familiar with. These include excitons, which are composed of an electron and a “hole,” or the space left behind when light is shone on a material and energy from a photon causes an electron to jump out of its usual position.

Through the mysteries of quantum mechanics, however, the electron and hole are still connected and can “communicate” with each other through electrostatic interactions. This interaction leads to a new composite particle formed by the electron and the hole — an exciton.

Excitons, unlike electrons, have no charge but possess spin. The spin can be thought of as an elementary magnet, in which the electrons are like little needles orienting in a certain way. In a common refrigerator magnet, the spins all point in the same direction. Generally speaking, the spins can organize in other patterns leading to different kinds of magnets. The unique magnetism associated with the nickel dihalides is one of these less-conventional forms, making it appealing for fundamental and applied research.

The MIT team explored how excitons form in the nickel dihalides. More specifically, they identified the exact energies, or wavelengths, of light necessary for creating them in the three materials they studied.

“We were able to measure and identify the energy necessary to form the excitons in three different nickel halides by chemically ‘tuning,’ or changing, the halide atom from chlorine to bromine to iodine,” says Occhialini. “This is one essential step towards understanding how photons — light — could one day be used to interact with or monitor the magnetic state of these materials.” Ultimate applications include quantum computing and novel sensors.

The work could also help predict new materials involving excitons that might have other interesting properties. Further, while the studied excitons originate on the nickel atoms, the team found that they do not remain localized to these atomic sites. Instead, “we showed that they can effectively hop between sites throughout the crystal,” Occhialini says. “This observation of hopping is the first for these types of excitons, and provides a window into understanding their interplay with the material’s magnetic properties.”

A special instrument

Key to this work — in particular for observing the exciton hopping — is resonant inelastic X-ray scattering (RIXS), an experimental technique that co-authors Pelliciari and Bisogni helped pioneer. Only a few facilities in the world have advanced high energy resolution RIXS instruments. One is at Brookhaven. Pelliciari and Bisogni are part of the team running the RIXS facility at Brookhaven. Occhialini will be joining the team there as a postdoc after receiving his MIT PhD.

RIXS, with its specific sensitivity to the excitons from the nickel atoms, allowed the team to “set the basis for a general framework for nickel dihalide systems,” says Pelliciari. “it allowed us to directly measure the propagation of excitons.”

This work was supported by the U.S. Department of Energy Basic Energy Science and Brookhaven National Laboratory through the Co-design Center for Quantum Advantage (C2QA), a DoE Quantum Information Science Research Center.

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