News

Postings created for publication in the Physics Department web page news feed.

An anomalous moment for the muon

Mark Rayner/CERN

The Fermilab E989 experiment announced the first new result on the muon’s anomalous magnetic moment in almost 20 years. The new measurement, combined with Brookhaven’s E821, has increased the discrepancy with the Standard Model value to 4.2 standard deviations. UConn Professors Tom Blum and Luchang Jin explain the theory calculations in a feature story in the Cern Courier.

Professor Nora Berrah Awarded a Blaise Pascal Chaire d’Excellence to Conduct Research in France

Professor of Physics Nora Berrah has been awarded the International Blaise Pascal Chaire d’Excellence, a prestigious honor whose previous winners include scientists and scholars from a wide range of disciplines, including multiple Nobel laureates. Her award was selected by a committee of scientists and voted on by the Permanent Commission Regional Council of the Région Île-de-France.

Prof. Berrah in her lab
Prof. Berrah in her laboratory.

This award is bestowed to scientists of international reputation who are invited to conduct research in the Paris area. The goal is to establish international collaborations and exchange, as well as share science globally. In Berrah’s case, the collaboration is between UConn and the Commissariat à l’énergie atomique et aux énergies alternatives de Saclay (CEA, Paris Saclay). The collaborative work is aimed to push the frontiers of science, as well as enrich and facilitate international research.

The Région Île-de-France selects every year four  laureates of high international standing in their field of expertise. All research areas are included, such as the humanities, arts, and sciences, in the selection of the awardees. Six Nobel laureates have been selected for the award since 1996. Prof. Berrah was selected by the Blaise Pascal Chaire Committee for the field of Fundamental Physics.

For more information about Professor Berrah’ award, see the article in UConn Today

Professor Munirul Islam: Celebrating His Life and His Legacy

Dear Colleagues:

I would like to share some thoughts on Munir Islam who recently passed away. Prof. Islam came to UConn in 1967 from a faculty position at Brown University. In the late 1970s there were two particle theorists at UConn, Profs. Kurt Haller and Munir Islam. They set about building an elementary-particle theory program here and garnered the support of then Physics Head Joe Budnick and CLAS Dean Julius Elias. They soon obtained funding for a new Department of Energy initiative to support particle theory in the Department. In 1979 they
were able to bring me in as an Associate Professor and Mark Swanson as an Assistant Professor. So eager were Kurt and Munir to bring us in, they chose to forego the summer salary that they had been awarded on the DOE grant.  The impact of the DOE grant on the UConn administration was quite far reaching and led to further internal support. Within a few years I had been tenured and promoted to Full and Mark had been tenured and appointed to Associate at our Stamford branch, where he later became an administrator.

After that, Kurt and Munir were able to secure a bridge position with the DOE that would provide five years of support, provided the UConn administration would create a tenure track position for the recipient. This they agreed to do, and so we brought in Daniel Caldi at the Assistant level, who subsequently was appointed Associate with tenure. Dan eventually opted to leave us for SUNY Buffalo, but our particle group was then able to convince the UConn administration to let us keep the position, and we then hired Gerald Dunne. Gerald went up the ladder very quickly to tenured Full professor. The success of our program enabled us subsequently to bring in Alex
Kovner, followed by Tom Blum (both now tenured Full) and current Assistant Luchang Jin. The success and endurance of the particle group for more than forty years now is a testament to the foresight and the unwavering and unabating commitment of Kurt and Munir to it, and it serves as permanent memorial to both of them.

Munir Islam always retained an enthusiasm for research, an enthusiasm which did not diminish at all after he retired. He focused on fundamental problems in particle physics, with particular emphasis on the theory of the structure of the proton as revealed by high-energy proton-proton scattering. This is perhaps best evidenced in what essentially became a lifelong collaboration with his former graduate student Richard Luddy (at the right, with Prof Islam at the left in the above photograph) as the two of them grappled with Munir’s deep ideas on proton scattering during many of Munir’s later years as a Professor and then as an Emeritus. Munir had a gift for simple pictorial explanations of his research, which he was able to explain lucidly in a lecture for visiting high-school teachers and students during an open house. Munir was urbane, worldly, and wise, and it was a great joy to have him not just as a colleague but also as a friend. He will be sorely missed by all of those that knew him and especially by me as my career owes so much to him. In appreciation, Philip Mannheim.In appreciation,

Philip Mannheim.

The passing of Dr. David Katzenstein, a friend and benefactor of the UConn Department of Physics

Dr. David Katzenstein, a friend, and benefactor of the UConn Department of Physics, passed away on January 25, 2021 due to Covid-19. David was the son of Henry Katzenstein, the first Physics Ph.D. from UConn and a major benefactor of our Department. Currently, both the annual Katzenstein Distinguished Lecture and the Katzenstein Prize for a senior, undergraduate paper were endowed by the Katzenstein family.

David himself was an Emeritus Professor of Medicine at the Stanford University Medical School, specializing in Infectious Diseases and Geographic Medicine. He focused on the treatment and prevention of HIV-AIDS, particularly in sub-Saharan Africa. He died in Harare, Zimbabwe where he had moved in 2016 to continue his important work after his retirement from Stanford.

Obituary in NYTimes: David Katzenstein, AIDS Researcher With Focus on Africa, Dies at 69

A Signal from Beyond

Looking for ripples in the fabric of spacetime.

UConn astrophysicist Chiara Mingarelli is part of a team of researchers who recently published data on a hint of a signal that sent ripples of excitement through the physics community. These monumental findings are the culmination of twelve and a half years of data gathered from NANOGrav — a network of pulsars across the galaxy — all in the hopes of detecting gravitational waves.

Gravitational waves are generated when galaxies merge and supermassive black holes at their centers collide and send low-frequency gravitational waves out into the universe. The team thinks the source of the signal could be gravitational waves, but it will take about 2 more years of data to be sure.

The findings sparked the interest of other physicists with their own speculations about the signal, such as cosmic strings or primordial black holes. Though still a couple of years away, Mingarelli says the final results could also help test General Relativity or even open the door to entirely new physics.

This article first appeared on UConn Today, February 15, 2021

UConn Physics alumnus Dr. Michael Wininger

UConn Physics alumnus Dr. Michael Wininger (BS, 2003) was recently featured in the professional journal O&P Almanac (Orthotics and Prosthetics). The article describes how his eclectic background, beginning with degrees from UConn, has enabled him to lead innovations in several areas of health research. Mike is currently an Assistant Clinical Professor in the Biostatistics Department at the Yale School of Public Health while also holding a co-appointment with the Department of Veterans Affairs Cooperative Studies Program. Michael says that former Professor Ed Pollack was particularly instrumental in mentoring towards a successful career, and in gratitude has been a frequent contributor to the Edward Pollack Endowment Fund, which supports our annual Pollack Lecture in Atomic Physics. Some of the old-timers around the department remember Mike for his always energetic presence around the department and help with our bicycles.

UConn Researcher an Architect for Astronomical Survey Making Observations Toward a New Understanding of the Cosmos

November 2, 2020 – Elaina Hancock – UConn Communications

The Sloan Digital Sky Survey’s fifth generation – a groundbreaking project to bolster our understanding of the formation and evolution of galaxies, including the Milky Way – collected its very first observations on the evening of October 23.

Image: The Sloan Digital Sky Survey’s fifth generation made its first observations earlier this month. This image shows a sampling of data from those first SDSS-V data. The central sky image is a single field of SDSS-V observations. The purple circle indicates the telescope’s field-of-view on the sky, with the full Moon shown as a size comparison. SDSS-V simultaneously observes 500 targets at a time within a circle of this size. The left panel shows the optical-light spectrum of a quasar–a supermassive black hole at the center of a distant galaxy, which is surrounded by a disk of hot, glowing gas. The purple blob is an SDSS image of the light from this disk, which in this dataset spans about 1 arcsecond on the sky, or the width of a human hair as seen from about 21 meters (63 feet) away. The right panel shows the image and spectrum of a white dwarf — the left-behind core of a low-mass star (like the Sun) after the end of its life.Image Credit: Hector Ibarra Medel, Jon Trump, Yue Shen, Gail Zasowski, and the SDSS-V Collaboration. Central background image: unWISE / NASA/JPL-Caltech / D.Lang (Perimeter Institute).

“In a year when humanity has been challenged across the globe, I am so proud of the worldwide SDSS team for demonstrating — every day — the very best of human creativity, ingenuity, improvisation, and resilience. It has been a wild ride, but I’m happy to say that the pandemic may have slowed us, but it has not stopped us,” says Juna Kollmeier, director of the project known as SDSS-V.

The project is funded primarily by an international consortium of member institutions, along with grants from the Alfred P. Sloan Foundation, U.S. National Science Foundation, and the Heising-Simons Foundation.

Jonathan Trump, UConn assistant professor of physics, has a long history with SDSS, and is one of the architects for the fifth installment of the program. He is also serving as the cadence coordinator for the project’s black hole science goals.

“My very first undergrad research project was an SDSS project. I have worked on SDSS as a post-doc, and I am working on it now as faculty,” Trump says. “I’ve been part of it from the first SDSS iteration, and as it has taken off, so has my career.”

Trump and his colleagues will focus on three primary areas of investigation with SDSS-V, each exploring different aspects of the cosmos using different spectroscopic tools. Together, these three project pillars—called “Mappers”—will observe more than six million objects in the sky, and monitor changes in more than a million of those objects over time.

The survey’s Local Volume Mapper will enhance our understanding of galaxy formation and evolution by probing the interactions between the stars that make up galaxies and the interstellar gas and dust that is dispersed between them. The Milky Way Mapper will reveal the physics of stars in our Milky Way, the diverse architectures of its star and planetary systems, and the chemical enrichment of our galaxy since the early universe. The Black Hole Mapper will measure masses and growth over cosmic time of the supermassive black holes that reside in the hearts of galaxies, as well as the smaller black holes left behind when stars die.

Trump says another novel aspect of SDSS-V is repeat observation, which he will be scheduling over the duration of the project as cadence coordinator, to help gather more data about the evolution of different features of matter near black holes.

“SDSS-V has more repeat observations as part of the plan. I would say that broadly in astronomy there is an emphasis on repeat observations,” he says. “For instance, black holes are fascinating – they are rips in space-time, and they are extremely exotic. Even one snapshot reveals how exotic they are, but they are also dramatically variable, and when we observe them day-to-day, week-to-week, year-to-year, we see dramatic changes in their emission, which we think correspond to dramatic changes just beyond the event horizon of the black hole. We are learning that you can reveal a lot about the physics of what is going on around black holes by watching them as a function of time.”

SDSS-V will operate out of both Apache Point Observatory in New Mexico, home of the survey’s original 2.5-meter telescope, and Carnegie’s Las Campanas Observatory in Chile, where it uses the 2.5-meter du Pont telescope. SDSS-V’s first observations were gathered in New Mexico with existing SDSS instruments, as a necessary change of plans due to the pandemic. As laboratories and workshops around the world navigate safe reopening, SDSS-V’s own suite of new innovative hardware is on the horizon—in particular, systems of automated robots to aim the fiber optic cables used to collect the light from the night sky. These will be installed at both observatories over the next year. New spectrographs and telescopes are also being constructed to enable the Local Volume Mapper observations.

Trump points out that another important aspect of SDSS, especially in a time of remote learning and researching, is the fact that data are made public and accessible.

“It is easy to access and mine the SDSS databases and make interesting studies,” he says. “They have wonderful tutorials for schools and for researchers to get started. They make it so easy for people to dive in. It is a very rich opportunity; it’s well organized and publicly shared.”

To learn more about the program, explore the data, or keep up with the research, visit https://www.sdss5.org/

This article first appeared online on UConn Today, November 2, 2020.

The passing of UConn Physics Professor Emeritus, Arnold Russek

Arnold Russek, a theoretical atomic physicist, born July 13, 1926, in New York, passed away on October 13th, 2020, in Colorado. As a young man of 18, he served honorably as a radio engineer in the Pacific during WWII. He earned his Ph.D. at the Courant Institute at New York University in 1953, and taught physics for 40 years at the University of Connecticut, having Professor Emeritus status when he retired in 1992. Prof. Russek published notable works on processes on hydrogen beams and atomic collisions. He is remembered by many of his students as not only an excellent teacher but also a kind and supportive mentor.

 

 

AAS Author Interview with Gloria Fonseca Alvarez

October 14, 2020 – AAS Author Interview Series

UConn graduate student Gloria Fonseca Alvarez was featured with a video in the Author Interview series produced by the American Astronomical Society (AAS):

 

In this video, Gloria talks about her work to understand the inner environments of black holes. The paper highlighted in the video shows that the orbits of emission-line gas around supermassive black holes are often smaller than expected from previous observations. We’re very proud to see Gloria’s exciting work recognized in the AAS Author Series!

Stretching Makes Superconductor

October 12, 2020 – Kim Krieger – UConn Communications

When people imagine new materials, they typically think of chemistry. But UConn physicist Ilya Sochnikov has another suggestion: mechanics.

Sochnikov works with superconductors. Superconductors are materials that let electricity flow without losing energy. In a normal conductor — say, a power line — electric current is gradually whittled down by friction and loss. We lose as much as 90% of the electricity we generate this way. But an electric current could flow through a superconducting circuit forever, unchanging. Practical superconductors would make power grids and many devices, including new computers, much more energy efficient.

Chemists and metallurgists have experimented with different combinations of elements for years, trying to get superconductors that work at temperatures close to room temperature (most superconductors only work when they are super cold.) The idea is to come up with the perfect combination of elements that will have exactly the right density of electrons, at the right energies. When that happens, electrons pair up and move through the material in a synchronized way, even at temperatures above 77 degrees Kelvin, which is the temperature of liquid nitrogen. That is considered a high-temperature superconductor, because liquid nitrogen is cheap to produce and can be used as a refrigerant. But finding the right chemistry to make new and better high-temperature superconductors has been elusive.

Sochnikov and his students are thinking about it differently. What if mechanical changes such as squeezing or stretching could make a material a superconductor? Changing the chemistry is ultimately about changing the arrangement of atoms and electrons in a material. Mechanical stresses can do the same thing, in a different way.

Along with Physics Department students Chloe Herrera, Jonah Cerbin, Donny Davino, and Jacob Franklin, Sochnikov designed a machine to stretch a small piece of superconductor to see what would happen. They picked strontium titanate, a well-known material used in high-tech electronics applications as big and almost perfect crystals, which becomes a superconductor around 0.5 degrees Kelvin. That is ridiculously cold, colder even than liquid helium. But strontium titanate behaves in a very weird way when it is that cold. Its atoms polarize; that means they all oscillate in synchrony. You can imagine them bouncing gently up and down, all together. These oscillations have a tendency to link electrons together, helping them move as a pair–this is probably what makes it superconduct.

Sochnikov and the students in the group knew that stretching strontium titanate would change how its atoms oscillated. That, in turn, might change how the electrons moved. The machine that stretches the crystal is made from copper to conduct heat away from the crystal. Most of the rest of the workings are coated in gold to reflect heat from the outside. It uses three cylinders to cool the material; first to the temperature of liquid nitrogen (70K), then liquid helium (4K), then to a boiling mixture of helium-3 and helium-4 (due to weird quantum effects, it is even colder than regular liquid helium–just a few thousandths of Kelvin! Really close to absolute zero!)

The whole setup is suspended in a steel frame that floats on shock absorbers, to prevent any vibrations in the floor from disturbing the experiment.

When Sochnikov, Herrera, Cerbin, Davino, and Franklin did the experiment and looked at the results, they found that stretched strontium titanate becomes superconducting at temperatures 40% higher than normal. That is a huge increase, percentage-wise. They believe it is because stretching the material makes it easier for the atoms to oscillate, gluing the electrons together more firmly. Now, they are working to calculate what made the difference, and plan on testing it in other materials in the near future.

“Usually we control materials chemically. Here, we do it mechanically. This gives us another tool to bring superconductors closer to everyday life, and to discover new functionalities,” Sochnikov says.

This article first appeared online on UConn Today, October 12, 2020.