Photo of Andrea Ghez

Andrea Ghez wins 2020 Nobel Prize in physics

Photo of Andrea Ghez

Andrea Ghez, UCLA’s Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics, has been awarded the 2020 Nobel Prize in physics. Photo Credit: Elena Zhukova

Andrea Ghez, UCLA’s Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics, today was awarded the 2020 Nobel Prize in physics.

Ghez shares half of the prize with Reinhard Genzel of UC Berkeley and the Max Planck Institute for Extraterrestrial Physics. The Nobel committee praised them for “the discovery of a supermassive compact object at the centre of our galaxy.” The other half of the prize was awarded to Roger Penrose of the University of Oxford “for the discovery that black hole formation is a robust prediction of the general theory of relativity.”

In July 2019, the journal Science published a study by Ghez and her research group that is the most comprehensive test of Albert Einstein’s iconic general theory of relativity near the monstrous black hole at the center of our galaxy. Although she concluded that “Einstein’s right, at least for now,” the research group is continuing to test Einstein’s theory, which she says cannot fully explain gravity inside a black hole.

Ghez studies more than 3,000 stars that orbit the supermassive black hole. Black holes have such high density that nothing can escape their gravitational pull, not even light. The center of the vast majority of galaxies appears to have a supermassive black hole, she said.

“I’m thrilled and incredibly honored to receive a Nobel Prize in physics,” said Ghez, who is director of the UCLA Galactic Center Group. “The research the Nobel committee is honoring today is the product of a wonderful collaboration among the scientists in the UCLA Galactic Center Orbits Initiative and the University of California’s wise investment in the W.M. Keck Observatory.

“We have cutting-edge tools and a world-class research team, and that combination makes discovery tremendous fun. Our understanding of how the universe works is still so incomplete. The Nobel Prize is fabulous, but we still have a lot to learn.”

UCLA Chancellor Gene Block lauded Ghez for her accomplishments.

“The UCLA community is exceedingly proud of Professor Ghez’s achievements, including this extraordinary honor,” Block said. “We are inspired by her research uncovering the secrets of our universe and its potential to help us better understand the cosmos.”

David Haviland, chair of the Nobel Committee for Physics, said: “The discoveries of this year’s Laureates have broken new ground in the study of compact and supermassive objects. But these exotic objects still pose many questions that beg for answers and motivate future research. Not only questions about their inner structure, but also questions about how to test our theory of gravity under the extreme conditions in the immediate vicinity of a black hole.”

Ghez and her team have made direct measurements of how gravity works near a supermassive black hole — research she describes as “extreme astrophysics.”

Einstein’s general theory of relativity is the best description of how gravity works. “However, his theory is definitely showing vulnerability,” Ghez said in 2019. “[A]t some point we will need to move beyond Einstein’s theory to a more comprehensive theory of gravity that explains what a black hole is.”

Less than two months after her publication in Science, she and her research group reported in Astrophysical Journal Letters the surprising finding that the supermassive black hole is having an unusually large meal of interstellar gas and dust — and they do not yet understand why.

“We have never seen anything like this in the 24 years we have studied the supermassive black hole,” she said at the time. “It’s usually a pretty quiet, wimpy black hole on a diet. We don’t know what is driving this big feast.”

In January 2020, her team reported the discovery of a new class of bizarre objects — objects that look like gas and behave like stars — at the center of our galaxy, not far from the supermassive black hole.

Ghez and her team conducted their research at the W.M. Keck Observatory in Hawaii. They are able to see the impact of how space and time get comingled near the supermassive black hole, which is some 26,000 light-years away.

“Making a measurement of such fundamental importance has required years of patient observing, enabled by state-of-the-art technology,” Richard Green, director of the National Science Foundation’s division of astronomical sciences, said in 2019.

“Andrea is one of our most passionate and tenacious Keck users,” Keck Observatory director Hilton Lewis said, also in 2019. “Her latest groundbreaking research is the culmination of unwavering commitment over the past two decades to unlock the mysteries of the supermassive black hole at the center of our Milky Way Galaxy.”

The National Science Foundation funded Ghez’s research for the past 25 years. More recently, her research has also been funded by the W.M. Keck Foundation, the Gordon and Betty Moore Foundation and the Heising-Simons Foundation, Lauren Leichtman and Arthur Levine, and Howard and Astrid Preston.

In 1998, Ghez answered one of astronomy’s most important questions, helping to show that a supermassive black hole resides at the center of the Milky Way galaxy. The question had been a subject of much debate among astronomers for more than a quarter of a century.

Ghez helped pioneer a powerful technology called adaptive optics, which corrects the distorting effects of the Earth’s atmosphere in real time and opened the center of our galaxy as a laboratory for exploring black holes and their fundamental role in the evolution of the universe. With adaptive optics at the Keck Observatory, she and her colleagues have revealed many surprises about the environments surrounding supermassive black holes, discovering, for example, young stars where none were expected and a lack of old stars where many were anticipated.

In 2000, Ghez and her research team reported that for the first time, astronomers had seen stars accelerate around the supermassive black hole. In 2003, she and her team reported that the case for the Milky Way’s black hole had been strengthened substantially and that all of the proposed alternatives could be excluded.

In 2005, Ghez and her colleagues took the first clear picture of the center of the Milky Way, including the area surrounding the black hole, at the Keck Observatory.

Ghez has earned numerous honors for her research, including election to the National Academy of Sciences and the American Academy of Arts and Sciences; she was the first woman to receive the Royal Swedish Academy of Sciences’ Crafoord Prize, and she was named a MacArthur Fellow in 2008. In 2019, she was awarded an honorary degree by Oxford University.

She earned a bachelor’s degree in physics from MIT in 1987 and a doctorate from Caltech in 1992, and she has been a member of the UCLA faculty since 1994. When she was young, she wanted to be the first woman to walk on the moon.

Ghez is the eighth UCLA faculty member to be named a Nobel laureate, joining Willard Libby (chemistry, 1960), Julian Schwinger (physics, 1965), Donald Cram (chemistry, 1987), Paul Boyer (chemistry, 1997), Louis Ignarro (physiology or medicine, 1998), Lloyd Shapley (economics, 2012) and J. Fraser Stoddart (2016). Stoddart was a Northwestern University faculty member when he received the honor, but much of the work for which he was recognized was conducted at UCLA from 1997 to 2008.

In addition, seven UCLA alumni have been awarded the Nobel Prize.

Ghez is also the fourth woman to receive the physics prize, following Marie Curie in 1903, Maria Goeppert Mayer in 1963 and Donna Strickland in 2018.

This article, written by Stuart Wolpert, originally appeared in the UCLA Newsroom.

A photo of Assistant Professor Wesley Campbell, UCLA Physics & Astronomy

UCLA physicists develop world’s best quantum bits

A photo of Assistant Professor Wesley Campbell, UCLA Physics & Astronomy

Assistant Professor Wesley Campbell, UCLA Physics & Astronomy (Photo Credit: UCLA)

A team of researchers at UCLA has set a new record for preparing and measuring the quantum bits, or qubits, inside of a quantum computer without error. The techniques they have developed make it easier to build quantum computers that outperform classical computers for important tasks, including the design of new materials and pharmaceuticals. The research is published in the peer-reviewed, online open-access journal, npj Quantum Information, published by Nature and including the exceptional research on quantum information and quantum computing.

Currently, the most powerful quantum computers are “noisy intermediate-scale quantum” (NISQ) devices and are very sensitive to errors. Error in preparation and measurement of qubits is particularly onerous: for 100 qubits, a 1% measurement error means a NISQ device will produce an incorrect answer about 63% of the time, said senior author Eric Hudson, a UCLA professor of physics and astronomy.

To address this major challenge, Hudson and UCLA colleagues recently developed a new qubit hosted in a laser-cooled, radioactive barium ion. This “goldilocks ion” has nearly ideal properties for realizing ultra-low error rate quantum devices, allowing the UCLA group to achieve a preparation and measurement error rate of about 0.03%, lower than any other quantum technology to date, said co-senior author Wesley Campbell, also a UCLA professor of physics and astronomy.

The development of this exciting new qubit at UCLA should impact almost every area of quantum information science, Hudson said. This radioactive ion has been identified as a promising system in quantum networking, sensing, timing, simulation and computation, and the researchers’ paper paves the way for large-scale NISQ devices.

Co-authors are lead author Justin Christensen, a postdoctoral scholar in Hudson’s laboratory, and David Hucul, a former postdoctoral scholar in Hudson and Campbell’s laboratories, who is now a physicist at the U.S. Air Force Research Laboratory.

The research is funded by the U.S. Army Research Office.

Campbell and Hudson are primary investigators of a major $2.7 million U.S. Department of Energy Quantum Information Science Research project to lay the foundation for the next generation of computing and information processing, as well as many other innovative technologies.

This article originally appeared on the UCLA Physical Sciences website.

Photos of UCLA College professors Jose Rodriguez and Erik Petigura.

Two UCLA College faculty members awarded 2020 Sloan Research Fellowships

Photos of UCLA College professors Jose Rodriguez and Erik Petigura.

UCLA College professors Jose Rodriguez (left) and Erik Petigura (right).

Two young UCLA College professors, and two others, are among 126 scientists and scholars from more than 60 colleges and universities in the United States and Canada selected today to receive 2020 Sloan Research Fellowships. UCLA is tied for fifth — behind only Stanford, UC Berkeley, UC San Diego and the Massachusetts Institute of Technology — in the number of faculty honored this year by the Alfred P. Sloan Foundation, which selects early-career scientists and scholars who are rising stars of science.

“To receive a Sloan Research Fellowship is to be told by your fellow scientists that you stand out among your peers,” says Adam F. Falk, president of the Alfred P. Sloan Foundation. “A Sloan Research Fellow is someone whose drive, creativity and insight make them a researcher to watch.”

Since the first Sloan Research Fellowships were awarded in 1955, 165 UCLA faculty members have received Sloan Research Fellowships. UCLA College’s 2020 recipients are:

Erik Petigura

Petigura, an assistant professor of physics and astronomy in the UCLA College, studies exoplanets — planets orbiting stars other than the sun — using ground-based and space-based telescopes. “My passion for exoplanets is motivated by a deceptively simple, yet fundamental question: Why are we here?” said Petigura. “Our species has wrestled with this question since antiquity, and it resonates strongly with me.” Exoplanets offer the key avenue toward answering this question, as they inform the otherwise elusive physical processes that led to the formation of the solar system, the formation of the Earth and the origin of life. His group has shown that nearly every sun-like star has a planet between the size of Earth and Neptune — sizes not present in the solar system. “In other words, our solar system is not a typical outcome of planet formation, at least in that one key respect,” he said. As a Sloan Fellow, Petigura plans to study the origin, evolution and fate of these ubiquitous planets.

Jose Rodriguez

Rodriguez, an assistant professor of chemistry and biochemistry in the UCLA College, develops and applies new scientific methods in bio-imaging to determine, and provide a deep scientific understanding of, cellular and molecular structures and reveal undiscovered structures that influence chemistry, biology and medicine. His research combines computational, biochemical and biophysical experiments. His laboratory is working to explore the structures adopted by prions — a form of infectious protein that causes neurodegenerative disorders. Prion proteins, like the amyloid proteins associated with Alzheimer’s disease, form large clumps that damage and ultimately kill neurons in the brain. Among his awards and honors, Rodriguez won a 2019 Packard fellowship for Science and Engineering by the David and Lucile Packard Foundation; a 2018 Pew scholar in the biomedical sciences, a 2017 Searle Scholar and a 2017 Beckman Young Investigator by the Arnold and Mabel Beckman Foundation.

Winners of Sloan Research Fellowships receive a two-year, $75,000 award to support their research. The fellowships are intended to enhance the careers of exceptional young scientists and scholars in chemistry, computer science, economics, mathematics, computational and evolutionary molecular biology, neuroscience, ocean sciences and physics. The Sloan Foundation, which is based in New York, was established in 1934.

This article originally appeared in the UCLA Newsroom.

Photo of orbits of the G objects at the center of our galaxy

Astronomers discover class of strange objects near our galaxy’s enormous black hole

Photo of orbits of the G objects at the center of our galaxy

Orbits of the G objects at the center of our galaxy, with the supermassive black hole indicated with a white cross. Stars, gas and dust are in the background. Photo: Anna Ciurlo, Tuan Do/UCLA Galactic Center Group

Astronomers from UCLA’s Galactic Center Orbits Initiative have discovered a new class of bizarre objects at the center of our galaxy, not far from the supermassive black hole called Sagittarius A*. They published their research in the Jan. 16 issue of the journal Nature.

“These objects look like gas and behave like stars,” said co-author Andrea Ghez, UCLA’s Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics and director of the UCLA Galactic Center Group.

The new objects look compact most of the time and stretch out when their orbits bring them closest to the black hole. Their orbits range from about 100 to 1,000 years, said lead author Anna Ciurlo, a UCLA postdoctoral researcher.

Ghez’s research group identified an unusual object at the center of our galaxy in 2005, which was later named G1. In 2012, astronomers in Germany made a puzzling discovery of a bizarre object named G2 in the center of the Milky Way that made a close approach to the supermassive black hole in 2014. Ghez and her research team believe that G2 is most likely two stars that had been orbiting the black hole in tandem and merged into an extremely large star, cloaked in unusually thick gas and dust.

“At the time of closest approach, G2 had a really strange signature,” Ghez said. “We had seen it before, but it didn’t look too peculiar until it got close to the black hole and became elongated, and much of its gas was torn apart. It went from being a pretty innocuous object when it was far from the black hole to one that was really stretched out and distorted at its closest approach and lost its outer shell, and now it’s getting more compact again.”

“One of the things that has gotten everyone excited about the G objects is that the stuff that gets pulled off of them by tidal forces as they sweep by the central black hole must inevitably fall into the black hole,” said co-author Mark Morris, UCLA professor of physics and astronomy. “When that happens, it might be able to produce an impressive fireworks show since the material eaten by the black hole will heat up and emit copious radiation before it disappears across the event horizon.”

But are G2 and G1 outliers, or are they part of a larger class of objects? In answer to that question, Ghez’s research group reports the existence of four more objects they are calling G3, G4, G5 and G6. The researchers have determined each of their orbits. While G1 and G2 have similar orbits, the four new objects have very different orbits.

Ghez believes all six objects were binary stars — a system of two stars orbiting each other — that merged because of the strong gravitational force of the supermassive black hole. The merging of two stars takes more than 1 million years to complete, Ghez said.

“Mergers of stars may be happening in the universe more often than we thought, and likely are quite common,” Ghez said. “Black holes may be driving binary stars to merge. It’s possible that many of the stars we’ve been watching and not understanding may be the end product of mergers that are calm now. We are learning how galaxies and black holes evolve. The way binary stars interact with each other and with the black hole is very different from how single stars interact with other single stars and with the black hole.”

Ciurlo noted that while the gas from G2’s outer shell got stretched dramatically, its dust inside the gas did not get stretched much. “Something must have kept it compact and enabled it to survive its encounter with the black hole,” Ciurlo said. “This is evidence for a stellar object inside G2.”

“The unique dataset that Professor Ghez’s group has gathered during more than 20 years is what allowed us to make this discovery,” Ciurlo said. “We now have a population of ‘G’ objects, so it is not a matter of explaining a ‘one-time event’ like G2.”

The researchers made observations from the W.M. Keck Observatory in Hawaii and used a powerful technology that Ghez helped pioneer, called adaptive optics, which corrects the distorting effects of the Earth’s atmosphere in real time. They conducted a new analysis of 13 years of their UCLA Galactic Center Orbits Initiative data.

In September 2019, Ghez’s team reported that the black hole is getting hungrier and it is unclear why. The stretching of G2 in 2014 appeared to pull off gas that may recently have been swallowed by the black hole, said co-author Tuan Do, a UCLA research scientist and deputy director of the Galactic Center Group. The mergers of stars could feed the black hole.

The team has already identified a few other candidates that may be part of this new class of objects, and are continuing to analyze them.

Ghez noted the center of the Milky Way galaxy is an extreme environment, unlike our less hectic corner of the universe.

“The Earth is in the suburbs compared to the center of the galaxy, which is some 26,000 light-years away,” Ghez said. “The center of our galaxy has a density of stars 1 billion times higher than our part of the galaxy. The gravitational pull is so much stronger. The magnetic fields are more extreme. The center of the galaxy is where extreme astrophysics occurs — the X-sports of astrophysics.”

Ghez said this research will help to teach us what is happening in the majority of galaxies.

Other co-authors include Randall Campbell, an astronomer with the W.M. Keck Observatory in Hawaii; Aurelien Hees, a former UCLA postdoctoral scholar, now a researcher at the Paris Observatory in France; and Smadar Naoz, a UCLA assistant professor of physics and astronomy.

The research is funded by the National Science Foundation, W.M. Keck Foundation and Keck Visiting Scholars Program, the Gordon and Betty Moore Foundation, the Heising-Simons Foundation, Lauren Leichtman and Arthur Levine, Jim and Lori Keir, and Howard and Astrid Preston.

In July 2019, Ghez’s research team reported on the most comprehensive test of Einstein’s iconic general theory of relativity near the black hole. They concluded that Einstein’s theory passed the test and is correct, at least for now.

► Watch a four-minute film about Ghez’s research

►View an animation below of the orbits of the G objects, together with the orbits of stars near the supermassive black hole. Credit: Advanced Visualization Lab, National Center for Supercomputing Applications, University of Illinois

This article originally appeared in the UCLA Newsroom.

That Supermassive Black Hole in our Galaxy? It has a Friend.

Two black holes are entwined in a gravitational tango in this artist’s conception. Photo Credit: NASA/JPL-Caltech/SwRI/MSSS/Christopher Go

Smadar Naoz is an associate professor of physics and astronomy in the UCLA College. She wrote this article for The Conversation.

Do supermassive black holes have friends? The nature of galaxy formation suggests that the answer is yes, and in fact, pairs of supermassive black holes should be common in the universe.

I am an astrophysicist and am interested in a wide range of theoretical problems in astrophysics, from the formation of the very first galaxies to the gravitational interactions of black holes, stars and even planets. Black holes are intriguing systems, and supermassive black holes and the dense stellar environments that surround them represent one of the most extreme places in our universe.

The supermassive black hole that lurks at the center of our galaxy, called Sgr A*, has a mass of about 4 million times that of our sun. A black hole is a place in space where gravity is so strong that neither particles or light can escape from it. Surrounding Sgr A* is a dense cluster of stars. Precise measurements of the orbits of these stars allowed astronomers to confirm the existence of this supermassive black hole and to measure its mass. For more than 20 years, scientists have been monitoring the orbits of these stars around the supermassive black hole. Based on what we’ve seen, my colleagues and I show that if there is a friend there, it might be a second black hole nearby that is at least 100,000 times the mass of the sun.

Supermassive black holes and their friends

Almost every galaxy, including our Milky Way, has a supermassive black hole at its heart, with masses of millions to billions of times the mass of the sun. Astronomers are still studying why the heart of galaxies often hosts a supermassive black hole. One popular idea connects to the possibility that supermassive holes have friends.

To understand this idea, we need to go back to when the universe was about 100 million years old, to the era of the very first galaxies. They were much smaller than today’s galaxies, about 10,000 or more times less massive than the Milky Way. Within these early galaxies the very first stars that died created black holes, of about tens to thousand the mass of the sun. These black holes sank to the center of gravity, the heart of their host galaxy. Since galaxies evolve by merging and colliding with one another, collisions between galaxies will result in supermassive black hole pairs – the key part of this story. The black holes then collide and grow in size as well. A black hole that is more than a million times the mass of our sun is considered supermassive.

If indeed the supermassive black hole has a friend revolving around it in close orbit, the center of the galaxy is locked in a complex dance. The partners’ gravitational tugs will also exert its own pull on the nearby stars disturbing their orbits. The two supermassive black holes are orbiting each other, and at the same time, each is exerting its own pull on the stars around it.

The gravitational forces from the black holes pull on these stars and make them change their orbit; in other words, after one revolution around the supermassive black hole pair, a star will not go exactly back to the point at which it began.

Using our understanding of the gravitational interaction between the possible supermassive black hole pair and the surrounding stars, astronomers can predict what will happen to stars. Astrophysicists like my colleagues and me can compare our predictions to observations, and then can determine the possible orbits of stars and figure out whether the supermassive black hole has a companion that is exerting gravitational influence.

Using a well-studied star, called S0-2, which orbits the supermassive black hole that lies at the center of the galaxy every 16 years, we can already rule out the idea that there is a second supermassive black hole with mass above 100,000 times the mass of the sun and farther than about 200 times the distance between the sun and the Earth. If there was such a companion, then I and my colleagues would have detected its effects on the orbit of SO-2.

But that doesn’t mean that a smaller companion black hole cannot still hide there. Such an object may not alter the orbit of SO-2 in a way we can easily measure.

The physics of supermassive black holes

Supermassive black holes have gotten a lot of attention lately. In particular, the recent image of such a giant at the center of the galaxy M87 opened a new window to understanding the physics behind black holes.

The proximity of the Milky Way’s galactic center – a mere 24,000 light-years away – provides a unique laboratory for addressing issues in the fundamental physics of supermassive black holes. For example, astrophysicists like myself would like to understand their impact on the central regions of galaxies and their role in galaxy formation and evolution. The detection of a pair of supermassive black holes in the galactic center would indicate that the Milky Way merged with another, possibly small, galaxy at some time in the past.

That’s not all that monitoring the surrounding stars can tell us. Measurements of the star S0-2 allowed scientists to carry out a unique test of Einstein’s general theory of relativity. In May 2018, S0-2 zoomed past the supermassive black hole at a distance of only about 130 times the Earth’s distance from the sun. According to Einstein’s theory, the wavelength of light emitted by the star should stretch as it climbs from the deep gravitational well of the supermassive black hole.

The stretching wavelength that Einstein predicted – which makes the star appear redder – was detected and proves that the theory of general relativity accurately describes the physics in this extreme gravitational zone. I am eagerly awaiting the second closest approach of S0-2, which will occur in about 16 years, because astrophysicists like myself will be able to test more of Einstein’s predictions about general relativity, including the change of the orientation of the stars’ elongated orbit. But if the supermassive black hole has a partner, this could alter the expected result.

Finally, if there are two massive black holes orbiting each other at the galactic center, as my team suggests is possible, they will emit gravitational waves. Since 2015, the LIGO-Virgo observatories have been detecting gravitational wave radiation from merging stellar-mass black holes and neutron stars. These groundbreaking detections have opened a new way for scientists to sense the universe.

Any waves emitted by our hypothetical black hole pair will be at low frequencies, too low for the LIGO-Virgo detectors to sense. But a planned space-based detector known as LISA may be able to detect these waves which will help astrophysicists figure out whether our galactic center black hole is alone or has a partner.

This article originally appeared in the UCLA Newsroom.

4d graphic rendering of iron-platinum nanoparticle

Atomic motion is captured in 4D for the first time

4d graphic rendering of iron-platinum nanoparticle

The image shows 4D atomic motion captured in an iron-platinum nanoparticle at three different times.
Credit: Alexander Tokarev

Results of UCLA-led study contradict a long-held classical theory

Everyday transitions from one state of matter to another — such as freezing, melting or evaporation — start with a process called “nucleation,” in which tiny clusters of atoms or molecules (called “nuclei”) begin to coalesce. Nucleation plays a critical role in circumstances as diverse as the formation of clouds and the onset of neurodegenerative disease.

A UCLA-led team has gained a never-before-seen view of nucleation — capturing how the atoms rearrange at 4D atomic resolution (that is, in three dimensions of space and across time). The findings, published in the journal Nature, differ from predictions based on the classical theory of nucleation that has long appeared in textbooks.

“This is truly a groundbreaking experiment — we not only locate and identify individual atoms with high precision, but also monitor their motion in 4D for the first time,” said senior author Jianwei “John” Miao, a UCLA professor of physics and astronomy, who is the deputy director of the STROBE National Science Foundation Science and Technology Center and a member of the California NanoSystems Institute at UCLA.

Research by the team, which includes collaborators from Lawrence Berkeley National Laboratory, University of Colorado at Boulder, University of Buffalo and the University of Nevada, Reno, builds upon a powerful imaging techniquepreviously developed by Miao’s research group. That method, called “atomic electron tomography,” uses a state-of-the-art electron microscope located at Berkeley Lab’s Molecular Foundry, which images a sample using electrons. The sample is rotated, and in much the same way a CAT scan generates a three-dimensional X-ray of the human body, atomic electron tomography creates stunning 3D images of atoms within a material.

Miao and his colleagues examined an iron-platinum alloy formed into nanoparticles so small that it takes more than 10,000 laid side by side to span the width of a human hair. To investigate nucleation, the scientists heated the nanoparticles to 520 degrees Celsius, or 968 degrees Fahrenheit, and took images after 9 minutes, 16 minutes and 26 minutes. At that temperature, the alloy undergoes a transition between two different solid phases.

Although the alloy looks the same to the naked eye in both phases, closer inspection shows that the 3D atomic arrangements are different from one another. After heating, the structure changes from a jumbled chemical state to a more ordered one, with alternating layers of iron and platinum atoms. The change in the alloy can be compared to solving a Rubik’s Cube — the jumbled phase has all the colors randomly mixed, while the ordered phase has all the colors aligned.

In a painstaking process led by co-first authors and UCLA postdoctoral scholars Jihan Zhou and Yongsoo Yang, the team tracked the same 33 nuclei — some as small as 13 atoms — within one nanoparticle.

“People think it’s difficult to find a needle in a haystack,” Miao said. “How difficult would it be to find the same atom in more than a trillion atoms at three different times?”

The results were surprising, as they contradict the classical theory of nucleation. That theory holds that nuclei are perfectly round. In the study, by contrast, nuclei formed irregular shapes. The theory also suggests that nuclei have a sharp boundary. Instead, the researchers observed that each nucleus contained a core of atoms that had changed to the new, ordered phase, but that the arrangement became more and more jumbled closer to the surface of the nucleus.

Classical nucleation theory also states that once a nucleus reaches a specific size, it only grows larger from there. But the process seems to be far more complicated than that: In addition to growing, nuclei in the study shrunk, divided and merged; some dissolved completely.

“Nucleation is basically an unsolved problem in many fields,” said co-author Peter Ercius, a staff scientist at the Molecular Foundry, a nanoscience facility that offers users leading-edge instrumentation and expertise for collaborative research. “Once you can image something, you can start to think about how to control it.”

The findings offer direct evidence that classical nucleation theory does not accurately describe phenomena at the atomic level. The discoveries about nucleation may influence research in a wide range of areas, including physics, chemistry, materials science, environmental science and neuroscience.

“By capturing atomic motion over time, this study opens new avenues for studying a broad range of material, chemical and biological phenomena,” said National Science Foundation program officer Charles Ying, who oversees funding for the STROBE center. “This transformative result required groundbreaking advances in experimentation, data analysis and modeling, an outcome that demanded the broad expertise of the center’s researchers and their collaborators.”

Other authors were Yao Yang, Dennis Kim, Andrew Yuan and Xuezeng Tian, all of UCLA; Colin Ophus and Andreas Schmid of Berkeley Lab; Fan Sun and Hao Zeng of the University at Buffalo in New York; Michael Nathanson and Hendrik Heinz of the University of Colorado at Boulder; and Qi An of the University of Nevada, Reno.

The research was primarily supported by the STROBE National Science Foundation Science and Technology Center, and also supported by the U.S. Department of Energy.

This story originally appeared in the UCLA Newsroom.

Andrea Ghez, Lauren B. Leichtman & Arthur E. Levine Chair in Astrophysics at UCLA, receiving an honorary doctorate from Oxford University on June 26, 2019. Ghez is with her sons.

UCLA astronomer receives honorary degree from Oxford

By Lisa Garibay

Andrea Ghez, Lauren B. Leichtman & Arthur E. Levine Chair in Astrophysics at UCLA, receiving an honorary doctorate from Oxford University on June 26, 2019. Ghez is with her sons.

UCLA’s Andrea Ghez with her sons at Oxford University.

Andrea Ghez, distinguished professor of physics and astronomy and director of UCLA’s Galactic Center Group, was awarded an honorary degree today from Oxford University during its annual Encaenia ceremony.

Ghez demonstrated the existence of a supermassive black hole at the center of our galaxy, with a mass 4 million times that of our sun. Her work provided the best evidence yet that these exotic objects really do exist, providing an opportunity to study the fundamental laws of physics in the extreme environment near a black hole, and learn what role this black hole has played in the formation and evolution of our galaxy.

She joins an eclectic group including cellist Yo-Yo Ma, Nobel laureate Daniel Kahneman, and UC Berkeley professor Jennifer Doudna, who developed the CRISPR-Cas9 technology for gene editing.

Ghez, who is the Lauren B. Leichtman & Arthur E. Levine Chair in Astrophysics, earned her bachelor’s degree in physics from MIT in 1987 and her doctorate from Caltech in 1992, and has been on the faculty at UCLA since 1994.

This article was originally published on the UCLA Newsroom.

UCLA leads development of first-of-its-kind telescope for gamma-ray astronomy

Researchers using the array will be able to study the gamma rays in the sky with the sensitivity 10 times better than currently achieved. This will help to address some of the most important and perplexing questions in very-high-energy astrophysics.

Space physicist wins Royal Astronomical Society 2019 Gold Medal

Margaret Kivelson, who discovered an ocean inside Jupiter’s moon Europa and a magnetic field generated by neighboring Ganymede, has been awarded the Royal Astronomical Society’s 2019 Gold Medal.