Their method for introducing machine learning in chemistry classes has been honored with the inaugural James C. McGroddy Award for Innovation in Education, named for a donor who funded the award’s cash prize. (See related story.)

The recipients are Elizabeth Thrall, Ph.D., assistant professor of chemistry; Yijun Zhao, Ph.D., assistant professor of computer and information science; and Joshua Schrier, Ph.D., the Kim B. and Stephen E. Bepler Chair in Chemistry. They will share the $10,000 prize, awarded in April.

Chemistry and Computation Come Together

The three awardees’ project shows how to reduce the barriers to learning about programming and computation by integrating them into chemistry lessons. The project came together during the COVID pandemic—since chemistry students were working from their computers, far from the labs on campus, it made sense to give them some computational projects, in addition to experiments they could conduct at home, Thrall said.

Because little had been published about teaching machine learning to chemistry students, she got together with Schrier and Zhao to design an activity. Zhao, director of the Master of Science in Data Science program at Fordham, involved a student in the program, Seung Eun Lee, GSAS ’22, who had studied chemistry as an undergraduate.

Their first classroom project—published in the Journal of Chemical Education in 2021—involves vibrational spectroscopy, used to identify the chemical properties of something by shining a light on it and recording which wavelengths it absorbs. Students built models that analyzed the resulting data and “learned” the features of different molecular structures, automating a process that they had learned in an earlier course.

For another project, the professors taught students about machine-learning tools for identifying possible hypotheses about collections of molecules. Machine learning lets the students winnow down the molecular data and, in Schrier’s words, “make that big haystack into a smaller haystack” that is easier for a scientist to manage. The professors designed the project with help from Fernando Martinez, GSAS ’23, and Thomas Egg, FCRH ’23, and Thrall presented it at an American Chemical Society meeting in the spring.

Thumbs-Up from Students

How did students react to the machine learning lessons? According to a survey following the first project, 63% enjoyed applying machine learning, and 74% wanted to learn more about it.

“I think that students recognize that these are useful skills … that are only going to become more important throughout their lives,” Thrall said. Schrier noted that students have helped develop additional machine learning exercises in chemistry over the past two years.

Machine Learning in Education and Medicine

Zhao noted the growing applications of machine learning and data science. She has applied them to other fields through collaborations with Fordham’s Graduate School of Education and the medical schools at New York University and Harvard, among other entities.

The McGroddy Award came as a surprise. “I don’t think that we expected to win,” Schrier said, “just because there’s so many other excellent pedagogical innovations throughout Fordham.”

Eva Badowska, Ph.D., dean of the Faculty of Arts and Sciences at the time the award was granted, said the professors’ “path-breaking interdisciplinary work has transformed lab courses in chemistry.”

There were 20 nominations, and faculty members reviewing them “were humbled by the creativity, innovation, and generative energy of the faculty’s pedagogical work,” she said.

In addition to the McGroddy Award, the Office of the Dean of Faculty of Arts and Sciences is providing two $1,000 honorable mention prizes recognizing the pedagogy of Samir Haddad, Ph.D., and Stephen Holler, Ph.D., associate professors of philosophy and physics, respectively.

Her California home is filled with what she calls her miniatures—expansive, intricate dollhouses depicting Lilliputian versions of scenes from her mystery novels. The miniatures, like their creator and her murderers, are careful, meticulous—every bit in its proper place, no table turned over but for plot.

“In the end, it’s all the same thing,” Minichino says. “Physics, mystery, even the houses. It’s about taking the unknown and working, step by step, to know it, to make it real.”

She is effortlessly eloquent discussing physics—in which she earned master’s and doctoral degrees from Fordham’s Graduate School of Arts and Sciences in the 1965 and 1968 before embarking on a long career studying and teaching high-temperature, high-pressure physics—and points out warmly that all physics is commanded by different flavors of quarks, including up, down, strange, and charm. “Come to think of it,” she says with a chuckle, “mystery stories are built on those same elements, too.”

She’s been to college three times. Now, at 82, she’s enrolled in school again, getting a second master’s degree in creative writing—a certification whose lack has always troubled her, regardless of the 27 novels to her name. She has no trouble explaining why, in spite of all her achievements, she’s back taking classes. “There’s so many days, still,” Minichino says, “and every day you’re not learning is a waste of a day.”

Minichino’s latest novel is Mousse and Murder (Berkley, 2020), the first book in the Alaskan Diner Mystery series she’s writing under the pen name Elizabeth Logan.

On July 30, the answer came from space: a call for human unity during a time of bitter conflicts, articulated by someone who is—quite literally—above it all.

“We watch the news up here every night, and we’re aware of what is going on in the world,” said Ricky Arnold, a NASA flight engineer aboard the International Space Station, speaking via live webcast. He cited the crew’s cooperative efforts as an example of what can happen when people from diverse nations work together.

Haig and her fellow interns watched from NASA’s Glenn Research Center in Cleveland.

“It was really exciting,” said Haig, who is getting ready for the fall quarter at Stanford, where she will pursue a master’s degree in aeronautics and astronautics.

The experience, part of a NASA educational program, fueled her enthusiasm for becoming an aerospace engineer and, hopefully, an astronaut herself one day. It also provided a thrilling coda to an undergraduate career that was heavy on science and grant-funded scientific research but also on classic humanistic aspects of Jesuit education.

Science Studies Inflected with Jesuit Values

Haig graduated summa cum laude from Fordham in May with a double major: engineering physics, with a concentration in mechanical engineering, and classical civilization. At NASA in Cleveland, she spent the summer in the ARETEP (Aeronautics Research and Engineering Team) program, studying the movement of urban air masses with an eye toward safety standards for new aerial vehicles that could one day be zipping around city skies.

Aviation is a longtime interest. In high school, she volunteered at an aviation museum near her Long Island home and enjoyed working with the museum’s elderly docents—an experience that led her to volunteer at Fordham as an aide to a former missionary—Richard Hoar, S.J.—living in the Murray-Weigel Hall retirement residence on the Rose Hill campus. “He actually has a master’s degree in physics, so it was a great fit,” Haig said.

A student in the honors program, she loved the program’s classics-related courses and kept signing up for more of them—Roman art, Latin, Greek. “Before I knew it, I had a major,” she said. For her senior thesis, she melded her two majors by examining how the Romans, known as great engineers, might have managed to fill the Colosseum with water for mock naval battles, as some have suggested they did.

There’s little evidence this happened. However, “the drains underneath the Colosseum are a lot larger than they would need to be just for rain water and waste water,” Haig said.

She also pursued varied scientific research projects. During the summer between sophomore and junior years, a Fordham Undergraduate Research Grant made it possible for her to work with physics professor Stephen Holler, Ph.D., on developing a new optical-fiber probe for use in analyzing tumors. For her second undergraduate research project, she worked at the Fermi National Accelerator Laboratory outside Chicago between junior and senior year and diagnosed a malfunction in the accelerator’s monitoring components.

She traveled to present her research at academic conclaves on the West Coast, thanks to travel grants provided by the University, and recently was awarded the Fordham College Alumni Association’s Undergraduate Research Symposium grant.

Haig suspects that her research helped her attain the NASA internship, a long-sought prize.

“I’ve been applying for the NASA program for a while, for at least a couple of summers, and I guess this summer I finally had enough research experience,” she said.

She found the internship to be a cornucopia for the scientifically curious. In addition to getting intensive introductions to aerodynamics and computational fluid dynamics, Haig has found scientists and engineers readily responsive to her email queries.

“I’ve found everybody to be so helpful and so willing to talk about their projects,” she said. “There are people working on missions that are going to Mars, stuff that’s going into deep space eventually. People say, ‘Yeah, come on over.’ I’ve been able to make so many connections.”

Aiming a Question at the Heavens

When she was chosen to record a question for the space station’s astronauts, she moved away from the technical and leaned toward the liberal arts, asking a question with a philosophical bent: “In today’s world, what is the most compelling reason to engage in human spaceflight?”

In his answer, Ricky Arnold, the NASA flight engineer, cited the scientific research conducted in space, as well as the crew’s perspective—“a higher plane of agreement”—on all the strife occurring far below.

“We have two Russians, three Americans, and a German right now,” he said, bobbing up and down in the zero gravity and casually moving his hands away from the microphone floating in front of him. “We have found something we all believe in, and the operations both here and on the ground are seamless because we all believe in the same thing. …

“There’s a really powerful message to all humans about what we as a species … are capable of when we put aside differences and focus on higher objectives as a species.”

Watch NASA astronaut Ricky Arnold’s webcast below. Bernadette Haig poses her question at the 5:22 mark. 

“In physics, we have a long tradition of theory and using mathematical models to describe complex systems. As neuroscience has been growing, it’s been bringing in a lot of people with training outside of biology to use some of that theory. I’m one of those people,” he said.

Albanna’s work combines physics, information theory, and statistical mechanics. The idea is that the same models that are used to predict the movement and interactions of atoms can also be applied to neurons as they’re interacting with each other in the brain.

Finding Order in the Chaos

“At a certain scale, that firing looks totally chaotic and random. But at the right scale, we can figure out what particular brain regions are doing, what your mind as a whole is doing, and how all that chaos comes together to give you a nice, predictable behavior,” he said.

In “Minimum and Maximum Entropy Distributions for Binary Systems with Known Means and Pairwise Correlations,” a paper he recently published in the journal Entropy, Albanna showed the range of entropies possible for neural models with specific properties.

In physics, entropy is a thermodynamic quantity that represents the unavailability of a system’s thermal energy that can be converted into mechanical work. Information theory provides another interpretation: entropy is also a way to measure the degree of uncertainty about the state of a system, or conversely, how much information we would need to understand exactly what state the system is in.

Albanna said that one way to comprehend that uncertainty is to imagine a standard cell phone contract. If one yes or no question’s worth of information is known as a “bit,” a 10-gigabyte cell phone plan is equivalent to about 100 billion bits – the answers to 100 billion yes or no questions – that the plan allows you to ask. Entropy describes everything else outside of that 100 billion.

The models borrowed from physics are referred to as “maximum entropy models,” Albanna said, because they are the models with the largest degree of uncertainty that are still consistent with the data at hand.

“People use the entropy of these models as a way to characterize how good a job these models are doing,” he said. “They’ll ask, ‘Does the entropy of the neural activity, or what you’re actually seeing in a real recorded data set, match up with what your model is predicting?’”

When it comes to modeling in physics, there are many reasons to feel confident that when the entropy of a system and the entropy of a model appear to match, the model is an accurate fit. It’s a lot harder in neuroscience though, because one can never really be sure which variables are the right ones to use in the model. Often, Albanna said, researchers pick whatever they can measure.

“You pick how often a neuron fires, but usually, you’re sort of groping around in the dark. You put your variables in and try to figure out whether you’re doing a good job. And you say, ‘Look, it matches up pretty well; the entropy is close.’ But we don’t know how poorly you could do.”

In his study, Albanna found that if a population of neurons behave interchangeably in a statistical sense, then any model consistent with the data gathered from monitoring of the cells will be a good fit in terms of the entropy. If this condition does not hold, the range of possible entropies is broad, and so these maximum entropy models are really capturing something important about the data.   

“It put some of these things that we are starting to take for granted in neuroscience on a little bit firmer footing, and showed we’re not cheating ourselves when we say these things do well,” he said.

The Gap between the Spikes

Another recent project that Albanna completed, a collaboration with a researcher from New York University’s School of Medicine, addresses the complexities of hearing.

Prior experiments with rats showed that it’s common that upon hearing a sound, only half the cortical cells in a part of the brain responsible for sound perception activate consistently. Though it may be tempting to focus exclusively on the cells that “light up” when prompted, Albanna said that’s a mistake. There is much to be learned from the other cells, he said.

“In fact, there are ways to show that these cells actually do respond. It looks like they may not be doing anything when you look through one lens, but if you look through the lens of our analysis, you can see that, in fact, they do carry information, at levels that are comparable to what those responsive cells are carrying.”

To do this, Albanna chose not to focus on the spikes that one sees when cells are activated. Instead, he focused on the gap between the spikes, known as the “interspike interval.” That’s where he found subtle differences that he said show how a particular cell is encoding information.

It’s still not clear what role the cells play in influencing rat behavior, but Albanna said the findings, which he and his co-author are submitting to the journal Nature Neuroscience, are an important first step.

Challenging Assumptions

Looking ahead, Albanna is in the process of developing graduate-level classes to accompany the undergraduate-level physics classes he teaches; the first will likely focus on psychophysics, which is the neuroscience of how perception works, for both through hearing and vision. He said he loves the field because unlike physics, it’s extremely young and in flux.

“There’s so much we don’t know, and so much of how you approach neuroscience depends on your perspective. Like, does this cell matter or not? We don’t always have concrete experimental answers to these questions yet, so you have to sort of build your view the best way you can, and then make sure that you’re always checking yourselves and challenging your assumptions,” he said.

Strange Glow: The Story of Radiation

Timothy Jorgensen is a scientist with a knack for narrative storytelling.

In Strange Glow, he relates the history of human experience with radiation—from William Roentgen’s 1895 discovery of X-rays to the recent Fukushima Daiichi nuclear power plant accident—in a style that’s largely free of scientific jargon and full of subtle humor and practical wisdom. He recounts the “hard-won lessons of how radiation helps and harms our health,” focusing not only on pioneering scientists like Roentgen, Thomas Edison, and Marie Curie but also on victims of the Fukushima disaster and the tragic story of the “radium girls,” factory workers who created glow-in-the-dark watch dials by using a fluorescent paint that contained radium.

Finally, and most practically, Jorgensen, a professor of radiation medicine and the director of the Health Physics and Radiation Protection Program at Georgetown University, addresses the risks of radiation exposure related to everyday cellphone use, diagnostic X-rays, full-body security scans, nuclear fallout, and the food we eat.

Not all forms of radiation are equally hazardous, he notes. For example, the dose of radiation we receive from a full-body scanner at the airport is extremely low compared to the background radiation at high altitudes. “The time we spend in the scanner results in the same dose that we receive from just 12 seconds of flying at high altitude,” he writes.

To ask whether a form of radiation is safe or dangerous misses the point. The question, Jorgensen writes, is whether or not the risk level is low enough that we shouldn’t be concerned—and not everyone has the same tolerance for risk. So his goal is not so much to dispel our fears of exposure but to present the facts as evenhandedly as possible.

“This book,” he writes, “seeks both to convince people that they can be masters of their own radiation fate, and to empower them to make their own well-informed decisions about their personal radiation exposures.”

By their very nature, black holes can never been seen. But thanks to advances in technology, scientists were able last year, for the very first time, to actually “listen” to two of them colliding with each other.

On April 7, Luca Matone, PhD, adjunct associate research scientist at the Columbia University Astrophysics Laboratory, explained how scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) in Washington and Louisiana accomplished something that even Albert Einstein never thought possible.

“That moment set the stage, because my job before was in science fiction; now, after [we heard]that ‘thump,’ it became science,” he told students at the Lincoln Center campus.

In his talk, “Listening to the Universe: The Observation of Gravitational Waves from a Binary Black Hole Merger,” Matone reviewed the theory of gravity as it was presented by Sir Isaac Newton and refined by Einstein. That theory, he explained, included the concept of a “fourth dimension” in which space-time is warped by objects such as the sun—or in this case two black holes.

When the two black holes collided and merged together some 1.3 billion years ago, the event released energy in the form of gravitational waves that rippled outward through space-time. (Matone said a good way to think about it would be to imagine a bowling ball placed on a trampoline. If you shook the ball, it would cause ripples on the trampoline surface.)

“When Albert Einstein proposed this [idea]in 1916, he dismissed it right away [even though]he knew that this was one of the consequences of general relativity. By putting the numbers in, he figured out 100 years ago that this was something that we could not possibly detect,” Matone said.

But Einstein surmised incorrectly. The collision/merger was detected on Sept. 14, 2015, using twin L-shaped laser interferometers in Livingston, Louisiana and Hanford, Washington that utilize lasers and suspended mirrors to achieve their incredible sensitivity to displacements.

Matone said that an enormous amount of energy was released when the black holes merged—one was about 36 times the mass of our sun; the other about 29 times the mass of our sun. The induced effect that was detected in September 2015 was at most 4 x10-18 meters—“an astounding, very, very small number.”

Matone played for the audience a clip of that sound, the signal that LIGO measured and simply sent it to a loudspeaker. A distinct “thump” could be heard. He also showed what the time series of the signal looked like on a graph.

“By observing these ripples, there’s a lot of information about the source. A lot of information about the source can be found just by looking at the frequency of oscillation of the ripples, the amplitude, and what kind of a wave form corresponds with it,” he said.

“Nowadays we have telescopes that can detect optical signals from the heavens. Now, with this machine, we have the ability to look at the universe with different eyes, or if you like, ears.”

The next challenge, he said, will be to build additional detectors that can help pinpoint the location of events. Currently, LIGO scientists listening to the sound of black holes colliding are like persons standing in a room with their eyes closed listening to voices. If asked to identity where in a room someone is talking, they can only point in a general direction. Additional detectors are under construction in India, Japan and Europe, and will make it easier to pinpoint exact locations.

These additions will lead to both cutting edge advances in technology and an expanded understanding of nature of our existence, he said.

“For the first time ever, we observed two merging black holes. No one has ever detected something like this,” he said.

“This is driven by a desire to understand the nature of the universe.”

Stephen Holler doesn’t have any barriers or flagmen stationed outside Freeman Hall, but make no mistake: the Rose Hill building is indeed a construction site.

Holler, an assistant professor of physics and engineering physics, is teaching “Modeling, Simulation, & Design” to undergraduates majoring in physics and engineering physics. The highlight of the class is three 3-D printers that students harness to construct objects as simple as trinkets or as complex as working catapults.  To do it, they learn how to use SolidWorks, a software package that’s the industry standard for mechanical design, and by extension the burgeoning 3-D printing industry.

“They can now create an object, apply forces to it and see how it deforms,” Holler said. “They’re taking their computer experiments and turning them into real world experiments.”

One of the challenges students are tasked with in the class is constructing trusses for a bridge, the strength of which they then have to test. Once students have calculated what the forces or stresses are on the object, they compare that with the simulation, Holler said, and then the actual model.

“They can test the real thing and prove to themselves that physics does actually work.”

Two of the printers extrude a biodegradable filament derived from cornstarch called polylactic acid; the third printer uses acrylonitrile butadiene styrene, a polymer often found in bottles, plates and cups.

Using the printers saves both time and money. They cut the amount of time it takes to construct a prototype of a piece of equipment from weeks to just a day. This is particularly useful if you realize that your original design is not the right one, said Holler— who recalled his own days of designing in the private sector before he came to Fordham.

He once designed a diagnostic tool for measuring mirror reflectivity, everything from the box to most of the components that went on the inside.

“But the way we had sketched one of the pieces was flipped from how the machinist read the drawing,” he said.

The end result, he said, was an expensive reworking—something that a 3-D printer would have likely eliminated.

Last year, for their final project, students were tasked with building catapults. This year they’re building cars, boats, and windmills. Their end project consists of a report with mechanical drawings, a physical model from the printer, and the results of stress, displacement, and frequency vibration testing.

Ryan Wichtowski, a senior engineering physics major, thinks that mastering SolidWorks will make him more employable. For his final project, Wichtowski is building a wind turbine that will require 7 to 10 individual parts. He hopes to go to law school and concentrate on intellectual property law, where 3-D printing is often utilized in creating models for patent applications.

“It is definitely an area of technology where there will be a lot of growth and development, so it would be good to get a good understanding of everything behind it,” he said.

For Stephen Holler, Ph.D., finding the utility of physics beyond the classroom is a cornerstone of his teaching technique and, indeed, his entire career.

The assistant professor of physics wants students to understand how physics works in the real world and to be able to communicate those complex ideas to anyone. 

“There’s more to it than going into a lab, turning a knob, and getting some data,” he said. “You have to be able to convey that experiment in a way that’s nontechnical.”

Besides teaching physics to pre-med students, Holler also teaches an advanced course in engineering physics that can be relevant in fields such as medicine or patent law. Regardless, communication remains key, he said.

Before coming to Fordham, Holler was well practiced in communicating with a wide variety of audiences. In graduate school he worked with the U.S. Army on biological aerosol detection. He later went on to work as a staff scientist at Sandia National Laboratories before joining a startup, NovaWave Technologies. NovaWave specialized in laser-based sensors that detect chemical and biological agents and eventually specialized in greenhouse gas monitoring. In 2010, Holler and his partners sold the company, and a year later he joined Fordham’s faculty.

It is that sensor technology expertise he brings to Fordham as he and his students build a lab that expands on groundbreaking work he completed last year with researchers from the Polytechnic Institute of New York University (NYU Poly) and the City University of New York (CUNY). That research detected the smallest known aqueous-borne RNA virus by using a device called a whispering gallery mode biosensor.

To explain by way of an anecdote, Holler said the concept of a whispering gallery is familiar to anyone who has ever been to the Oyster Bar at Grand Central Terminal. At a precise spot outside of the restaurant, if one whispers down toward the terrazzo floor, the whisper ricochets up onto the arched ceiling and into the ear of the listener standing about 20 feet away. To the listener, it sounds as though the whisperer were standing right beside him or her.

The whispering gallery biosensor operates in much the same way, Holler said. But instead of sound waves, light of different colors are “listened” to and the “speaker” is a laser. It’s a tunable laser, so the frequency (i.e., color) of the light can be controlled.

The system employs two fiber optics to harness and measure the light. One fiber is formed into a very small glass ball that is about a hundred microns in diameter, about the same as a strand of hair. This ball becomes the biosensor, aka the whispering gallery. Another smaller fiber measuring about five microns, or one-twentieth of a strand of hair, runs very close to the sphere but doesn’t touch it. It acts as a light guide. As a laser shoots through one end of the fiber, a sensor measures the amount of light that comes out at the other end.

And, as the laser is tunable, the frequency can be adjusted so as to allow just enough light to fall off into the biosensor, where its ricochet movements throughout the sphere can be measured.

When the sphere is coated with a virus or antibody, it creates a further change in the measurement. The process suggests another anecdote.

“Think of it as, if you ring a bell and then you add chewing gum to the bell, it’s going to change the resonance of that bell,” said Holler. “In this case the virus that you put onto the sphere is the chewing gum and the sphere is the bell.”

Last summer, Holler and the NYU Poly/CUNY team added gold nanoparticles to the sphere to create even smaller “hot spots.” It further increased the sphere’s sensitivity and enabled them to measure a single sample of the world’s smallest known RNA virus. The breakthrough was published in the July 30 issue of Applied Physics Letters.

Holler expects further breakthroughs, including a method of detecting protein that appears concurrent with certain cancers. Because of the sphere’s hypersensitivity, his hope is that it will be able to detect cancers earlier than current methods can.

Holler said that Fordham’s own whispering gallery biosensor should be completed later this summer, after which he plans to team up with Patricio Meneses, Ph.D., associate professor of biology, who has spent the last decade working on the human papillomavirus, or HPV.

“I have been working in this area for 10 years, so in about five years it would be nice to see the research commercialized, and of some benefit to those health professionals doing medical diagnostics,” said Holler.

A Fordham physics professor and his research collaborators at The Polytechnic Institute of New York University and City University of New York have created new nanotechnology to detect the world’s smallest known aqueous-borne virus.

Stephen Holler, Ph.D., and the researchers created a “plasmonic hybrid whispering gallery mode sensor,” which consists of a microscopic glass bead no wider than the thickness of a human hair (approximately 100 microns in diameter.) The bead has a single nanoscopic antenna affixed to it that–with the aid of light forces–can draw a single virus particle to a nanoplasmonic “hot spot.” Using a wavelength tunable laser source, the team then interprets the shifts in colors of light (i.e. resonances) that circumnavigate the glass bead, to detect and measure the size of the attracted virus–in this instance an RNA virus whose molecular weight is less than all known viruses.

Such direct object detection of a single bio-nano-particle of this size had previously been unattainable, said Holler.

This record-setting achievement was published in the July 30 issue of Applied Physics Letters, and subsequently highlighted by the American Institute of Physics.

Holler said the new discovery has numerous useful applications for identifying and studying biological particles, but more importantly for real-time medical diagnostics.

“Having achieved a detection limit below all known virus particle sizes means that medical diagnostic technology may soon be capable of rapidly detecting the presence of a single virion in blood or saliva – including common viruses such as influenza, HIV, Hepatitis and West Nile,” he said. “We envision doctors performing these tests in the office and getting results in minutes, not the days necessary for current blood tests. Early detection means immediate treatment, which can save lives.

“In addition, this sensor platform can serve as a sensitive device for monitoring for the presence of other biological and non-biological targets for medical (e.g., bacterial infection) and security applications (e.g., detection of biological or chemical warfare agents, explosives, and radiological/nuclear contamination).”

The researchers hope to soon push the detection limits further, and achieve single protein detection and characterization.

A Fordham physics professor and a colleague have confirmed the existence of a new form
of nuclear matter, one that they first predicted 25 years ago through theoretical studies.

The matter is composed of an eta meson trapped inside a nucleus, which they termed an eta-mesic nucleus. It is 100,000 times smaller than previously discovered mesic atoms.

Quamrul Haider, Ph.D., chair of the Department of Physics at Fordham, and Dr. Lon-chang Liu, staff physicist at Los Alamos National Laboratory, made the prediction in a paper published in 1986.

The paper, which has been cited in nearly 200 scholarly articles, helped to trigger many new fundamental studies in nuclear structure theory, and helped establish a new subfield in nuclear physics called “mesic nuclear physics.”

Attempts to confirm their prediction were conducted at sites around the world, including Los Alamos, the Brookhaven National Laboratory in New York and the Joint Institute for Nuclear Research in Dubna, Russia.

Then, the eta-mesic nucleus was detected in 2008 by a team of about 30 physicists from Germany, Poland, the United States, India, Bulgaria and Slovakia. This experimental discovery was made at Forschungszentrum Jülich in Germany, one of Europe’s largest interdisciplinary research centers.

The finding was published in the journal Physical Review in 2009.

Haider has spent the last three years poring over the data and conferring with Liu.

“A normal nucleus consists of a mixture of protons and neutrons. These particles are held together by a strongly attractive nuclear force between the nucleus’ constituents,” Haider said.

“An eta-mesic nucleus, on the other hand, is an exotic type of nuclear matter where, in addition to neutrons and protons, the eta meson is bound by the strong interaction inside a nucleus,” he said.

“In contrast with a normal nucleus, the exotic nucleus is at a higher energy state; the extra energy is due to the mass of the eta meson.”

Because experimental confirmation of theoretical predictions is the bedrock of a physicist’s work, Haider said he and Liu needed to wait before announcing their results.

“One experimental confirmation is not enough. We have to have a waiting period, in case someone says, ‘Well, I did the same experiment but did not notice anything,’” Haider said.

“The most important thing is that the Jülich experiment has proved the existence of the eta-mesic nucleus,” he said, “though the binding energy of the eta—or the amount of energy that appears to be released when this eta is taken out of the nucleus—deviates somewhat from our predicted value.

“This deviation arises because our original prediction made use of only the leading-order nuclear dynamics. After implementing higher-order corrections, we redid the calculations and found that the measurements agree with our theory now,” he said.

Haider presented their preliminary results in June 2010 at the International Symposium on Mesic Nuclei in Krakow, Poland.  The full work was published that year in Journal of Physics.

Next, Haider hopes to see physicists verify their calculations indicating that any nucleus lighter than Carbon-12 cannot support a bound state.

“Whether there is such a lower nuclear limit for forming the eta-mesic nucleus is of great importance to improving our understanding of mesic nuclear matter. There’s a big school of physicists who believe that this kind of nucleus also exists in lighter systems, like helium or lithium,” he said.

The matter is composed of an eta meson trapped inside a nucleus, which they termed an eta-mesic nucleus. It is 100,000 times smaller than previously discovered mesic atoms.

Quamrul Haider, Ph.D., chair of the Department of Physics at Fordham, and Dr. Lon-chang Liu, staff physicist at Los Alamos National Laboratory, made the prediction in a paper published in 1986.

The paper, which has been cited in nearly 200 scholarly articles, helped to trigger many new fundamental studies in nuclear structure theory, including a new subfield in nuclear physics called “mesic nuclear physics.”

Attempts to confirm their prediction had been conducted at sites around the world, including Los Alamos, the Brookhaven National Laboratory in New York and the Joint Institute for Nuclear Research in Dubna, Russia.

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Then, the eta-mesic nucleus was detected in 2008 by a team of about 30 physicists from Germany, Poland, the United States, India, Bulgaria and Slovakia. This experimental discovery was made at Forschungszentrum, Jülich in Germany, one of Europe’s largest interdisciplinary research centers.

The finding was published in the journal Physical Review in 2009.

Haider has spent the last three years poring over the data and conferring with Liu.

“A normal nucleus consists of a mixture of protons and neutrons. These particles are held together by a strongly attractive nuclear force between the nucleus’ constituents,” Haider said.

“An eta-mesic nucleus, on the other hand, is an exotic type of nuclear matter where, in addition to neutrons and protons, the eta meson is bound by the strong interaction inside a nucleus,” he said.

“In contrast with a normal nucleus, the exotic nucleus is at a higher energy state; the extra energy is due to the mass of the eta meson.”

Because experimental confirmation of theoretical predictions is the bedrock of a physicist’s work, Haider said they needed to wait before announcing their results.

“One experimental confirmation is not enough. We have to have a waiting period, in case someone says, ‘Well, I did the same experiment but did not notice anything,'” Haider said.

“The most important thing is that the Jülich experiment has proved the existence of the eta-mesic nucleus,” he said, “though the binding energy of the eta—or the amount of energy that appears to be released when this eta is taken out of the nucleus—deviates somewhat from our predicted value.

“This deviation arises because our original prediction made use of only the leading-order nuclear dynamics. After implementing higher-order corrections, we redid the calculations and found that the measurements agree with our theory now,” he said.

Haider presented their preliminary results in June 2010 at the International Symposium on Mesic Nuclei in Krakow, Poland.  The full work was published that year in Journal of Physics.

Next, Haider hopes to see physicists verify their calculations indicating that any nucleus lighter than Carbon-12 cannot support a bound state.

“Whether there is such a lower nuclear limit for forming the eta mesic nucleus is of great importance to improving our understanding of mesic nuclear matter. There’s a big school of physicists who believe that this kind of nucleus also exists in lighter systems, like helium or lithium,” he said.