Reports on recent events within the larger scientific world, with a member of the department explaining the science and commenting on its significance.

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

Cancelled: Professor Donna Strickland , Katzenstein Distinguished Lecturer


Dear Friends of UConn Physics,

Due to the current health situation and concerns surrounding the Corona virus, we are canceling the Katzenstein Lecture and Banquet scheduled for Friday, March 13, 2020.

It was an agonizing decision to cancel, but our first priority is the health of all who would have been attending, our special guest Professor Strickland, and the UConn community. I extend an extra apology for those of you who have planned to travel a considerable distance and will need to change plans. For those who have signed up for the banquet, we are working to arrange refunds.

If all goes well, the current health crisis will be behind us soon and we will see if we can reschedule Professor Strickland for another, safer time.

Again, my apologies and best wishes,

Barry Wells

Barrett O. Wells
Professor and Head, Department of Physics

The University of Connecticut, Department of Physics, is proud to announce that on March 13, 2020, Professor Donna Strickland of the Department of Physics and Astronomy at the University of Waterloo will be presenting the 2020 Distinguished Katzenstein Lecture. Prof. D. Strickland Prof. Strickland is one of the recipients of the 2018 Nobel Prize in Physics for developing chirped pulse amplification with Gérard Mourou, her PhD supervisor. They published this Nobel-winning research in 1985 when Strickland was a PhD student at the University of Rochester in New York State. Together they paved the way toward the most intense laser pulses ever created. The research has several applications today in industry and medicine — including the cutting of a patient’s cornea in laser eye surgery, and the machining of small glass parts for use in cell phones.

Prof. Strickland earned a Bachelor in Engineering from McMaster University and a PhD in optics from the University of Rochester. She was a research associate at the National Research Council Canada, a physicist at Lawrence Livermore National Laboratory and a member of technical staff at Princeton University. In 1997, she joined the University of Waterloo, where her ultrafast laser group develops high-intensity laser systems for nonlinear optics investigations. She is a recipient of a Sloan Research Fellowship, the Ontario Premier’s Research Excellence Award and a Cottrell Scholar Award. She received the Rochester Distinguished Scholar Award and the Eastman Medal from the University of Rochester.

Prof. Strickland served as the president of the Optical Society (OSA) in 2013 and is a fellow of OSA, the Royal Society of Canada, and SPIE (International Society for Optics and Photonics). She is an honorary fellow of the Canadian Academy of Engineering as well as the Institute of Physics. She received the Golden Plate Award from the Academy of Achievement, is in the International Women’s Forum Hall of Fame, and holds numerous honorary doctorates.

Livestream of the talk: March 13 2020, 4:00 EST, https://www.youtube.com/channel/UCBv2Kp9wAsjHDfEHhIRc0pg

Reception: at 3pm in the Gant Light Court

UConn seismometer detects Puerto Rico event


The Geophysics research group (Prof. Vernon Cormier and students) operate a seismic wave station that continuously monitors vibrations in the earth’s crust, many of which arise from seismic events that happen far away. These waves travel through the deep earth, and eventually make their way to the surface where they are detected. The above figures show high frequency and low frequency filtered seismograms recorded at UConn’s seismic station for the vertical component of ground motion from the earthquakes in Puerto Rico on January 7, 2020.  The 3 bursts of energy are P and S elastic waves, followed by a T wave, which propagates as an acoustic wave in the ocean.  In the high frequency seismogram (first figure), the large red trace is the main shock and the black trace below it is an aftershock. In the low frequency filtered seismogram (second figure), the largest energy propagates as a surface wave trapped in Earth’s crust and upper most mantle, with energy exponentially decaying into the mantle. Amplitude scale for ground particle velocity is shown by a bar in the upper left corner.

Research Spotlight: Exploring the nature of the universe with Dr. Thomas Blum

The Daily Campus published an article highlighting the research of Prof. Thomas Blum about Quantum Chromodynamics, a theory which describes the interactions between elementary particles. The development of this theory could help further understanding of the Standard Model of particle physics. The Standard Model is what physicists use to describe the fundamental building blocks of everything in the universe.

For more information follow the link.

Daniel McCarron wins NSF Early Career Award

Daniel McCarron, assistant professor of physics, the College of Liberal Arts and Sciences, will receive $645,000 over five years for his work on the development of techniques to trap large groups of molecules and cool them to temperatures near absolute zero. The possible control of molecules at this low temperature provides access to new research applications, such as quantum computers that can leverage the laws of quantum mechanics to outperform classical computers.

The NSF Faculty Early Career Development (CAREER) Program supports early-career faculty who have the potential to serve as academic role models in research and education, and to lead advances in the mission of their department or organization. Activities pursued by early-career faculty build a firm foundation for a lifetime of leadership in integrating education and research.

McCarron was one of 8 junior faculty at the University of Connecticut to receive the prestigious Early Career awards from NSF in 2019. For a description of all 8 awards, see this recent article published in UConn Today.

UConn Astronomers React to First Photo of a Black Hole

credit: Event Horizon Telescope collaboration

This image is the first ever taken of a black hole, captured by the Event Horizon Telescope (EHT) project. The black center is a direct view of the event horizon of a supermassive black hole with a mass of 6.5 billion times the Sun, lying at the center of the Virgo cluster of galaxies. The bright ring is emission from hot gas just above the event horizon, with an asymmetric shape caused by gravitational lensing of light in the strong gravity of the black hole. The EHT collaboration captured the image using a network of 8 radio telescopes that spanned the Earth, effectively creating a planet-sized interferometer.

For more information, see the full NSF press release:

This result directly impacts research in galaxy evolution and cosmology that is being carried out at UConn. The following comments from UConn Astrophysics researchers indicate the level of interest that this result has generated within the international Astrophysics community.

This is a stunning technical achievement. Supermassive black holes are the most extreme objects in the Universe, bizarre rips in spacetime that lie in the center of every massive galaxy. But despite their extreme properties, black holes have a remarkably simple mathematical description, with just a few numbers describing all of their vital properties: mass, size, and spin. Until now, the only way to measure black holes was through indirect methods, like my own research program that uses the timing of light echoes in the surrounding gas. The Event Horizon Telescope black hole image is a tremendous first step in a new understanding of extreme gravity and the detailed astrophysics of black holes. – Jonathan Trump, Assistant Professor
I am fascinated by this result and how we can actually see a direct image of a black hole that is a trillion times our distance to the Sun. This is truly an amazing result for human beings achieved within the limitation of our observational instruments. As an observational astronomer who works with black holes, this result also opens up new possibilities to learn about their unknown features such as black hole spin that could revolutionize our understanding of black hole physics. – Yasaman Homayouni, Graduate Student
This result is a beautiful demonstration of what is possible when the global community works in concert towards a scientific goal. Sometimes the greatest discoveries are not found by the biggest new telescopes in space, but through creative thinking, years of dedicated effort, and big data techniques, building upon what we have here on Earth. – Cara Battersby, Assistant Professor
It is truly extraordinary to be able to provide this new evidence for Einstein’s ideas on space and time through observations made no less than one hundred years since he first proposed them. As to the discovery itself, there are two aspects to black holes, one is that they pull everything in, and the other is that they do not let anything out. With nothing being able to get out, they thus look black to an observer on the outside, to thereby give them their black hole name. Now for many years we have had evidence of things falling into black holes, but had never previously had any evidence that things cannot get out. These new data show a fireball ring of things falling in, with the ring surrounding a black space in the center where nothing can get out. We thus confirm that indeed nothing can escape a black hole. – Philip Mannheim, Professor

For more about this topic, see this recent article in the Daily Campus, UConn Astronomy Community Responds Joyously to M87 Black Hole Image.

2 for the price of 1: UConn researcher finds new mechanism making double ionization an efficient process

Schematic of dICD

An international research team headed by Dr. Aaron LaForge from the research group of Prof. Nora Berrah in the Physics department at UConn has recently discovered a new type of decay mechanism leading to highly efficient double ionization in weakly-bound systems. The team has published its results in the science journal “Nature Physics”.

Ionization is a fundamental process where energetic photons or particles strip an electron from an atom or molecule. Normally, a much weaker process is double ionization, where two electrons are simultaneously emitted, since it requires higher-order interactions such as electron correlation. However, these new results show that double ionization doesn’t necessarily need to be a minor effect and can even be the primary ionization mechanism thereby getting two electrons for the price of one.

The enhancement is likely due to double ionization proceeding through a new type of energy transfer process termed double intermolecular Coulombic decay, or dICD, for short. The experiments were performed at the synchrotron, Elettra, in Trieste, Italy. There, electrons are accelerated to near the speed of light and then rapidly undulated through an alternating magnet field. In this way, the electrons emit short wavelength light which is needed to trigger dICD. The researchers produced superfluid helium droplets, which are cryogenic, nanometer-sized matrices capable of attaching various atomic and molecular species in order to perform precise spectroscopic measurements. In this case, dimers consisting of two alkali metal atoms were attached to the surface of helium droplets. The dICD process, schematically shown in Fig. 1, occurs through an electronically excited helium atom (red), produced by the synchrotron radiation, interacting with the neighboring alkali dimer (blue and white) resulting in energy transfer and double ionization. Although an alkali dimer attached to a helium nanodroplet is a model case, dICD is potentially relevant for any system where it is energetically allowed.

dICD belongs to a special class of decay mechanisms where energy is exchanged between neighboring atoms or molecules leading to enhanced ionization rates. Seemingly ubiquitous in weakly-bound, condensed phase systems such as van der Waals clusters or hydrogen-bonded networks like water, these processes can contribute to radiation damage of biological systems by producing particularly harmful low-energy electrons. dICD could strongly enhance such effects through the production of two low-energy electrons for each intermolecular decay.

Original publication:

A. C. LaForge, M. Shcherbinin, F. Stienkemeier, R. Richter, R. Moshammer, T. Pfeifer & M. Mudrich, “Highly efficient double ionization of mixed alkali dimers by intermolecular Coulombic decay”, Nature Physics (2019) DOI: 10.1038/s41567-018-0376-5

Kate Whitaker wins the Sloan Fellowship!

Original UConn Today article here

Rising Star in Astrophysics Receives Sloan Foundation Fellowship

Kate Whitaker, assistant professor of physics, stands next to a telescope inside the observatory on top of the Gant Complex on Feb. 14, 2019. (Peter Morenus/UConn Photo)
Kate Whitaker, assistant professor of physics, stands next to a telescope inside the observatory on top of the Gant Complex on Feb. 14, 2019. (Peter Morenus/UConn Photo)

As an assistant professor of astrophysics, Kate Whitaker spends a lot of her time thinking about stars. Hundreds of billions of stars that comprise galaxies, to be more precise. But with a recent fellowship from the Alfred P. Sloan Foundation, it is Whitaker’s star that is shining brightly.

Whitaker is one of 126 outstanding U.S. and Canadian researchers selected by the Alfred P. Sloan Foundation to receive 2019 Sloan Research Fellowships. The fellowships, awarded yearly since 1955, honor early-career scholars whose achievements mark them as among the most promising researchers in their fields.

Valued not only for their prestige, Sloan Research Fellowships are a highly flexible source of research support. Funds may be spent in any way a Fellow deems will best advance his or her work.

“Sloan Research Fellows are the best young scientists working today,” says Adam F. Falk, president of the Alfred P. Sloan Foundation. “Sloan Fellows stand out for their creativity, for their hard work, for the importance of the issues they tackle, and the energy and innovation with which they tackle them. To be a Sloan Fellow is to be in the vanguard of twenty-first century science.”

According to colleagues, Whitaker certainly fits the bill as one of the brightest young minds at UConn and beyond.

“Kate’s record so far is truly impressive and speaks to her potential as a leader in her field,” explains Barry Wells, head of UConn’s Department of Physics. “It was my great pleasure to nominate her for a Sloan Foundation Research Fellowship, and I am thrilled they felt she was worthy of the prize.”

An observational extragalactic astronomer, Whitaker’s research tries to reveal how galaxies are evolving from the earliest times to the present day.

In addition to her position at UConn, Whitaker is also an associate faculty at the new Cosmic Dawn Center in Copenhagen, Denmark. Whitaker and her students actively collaborate with DAWN, working towards pushing our detection of quiescent “red and dead” galaxies even earlier in time.

She will be among the world’s first scientists to explore the universe using the new James Webb Space Telescope when it is launched in 2019, which she says will allow her to push into new frontiers of research.

Apart from that exciting work, Whitaker and colleagues Cara Battersby and Jonathan Trump were tasked with building a full-fledged astronomy program from scratch at UConn. Not only has their work exceeded expectations, the fruits of their labor are already beginning to emerge. Whitaker and colleagues have so far created five new astrophysics courses with two more slated for next year, established an official astronomy minor, and are operating a thriving research program that involves doctoral students, undergrads, and even local high school students.

“I am both thrilled at this opportunity and humbled to be named amongst such a prestigious cohort of scientists,” says Whitaker. “With the Sloan Foundation’s generous support, I aspire to continue to lead ground-breaking studies of the distant universe, the mystery of which will no doubt captivate our imaginations.”

The Alfred P. Sloan Foundation is a philanthropic, not-for-profit grant making institution based in New York City. Established in 1934 by Alfred Pritchard Sloan Jr., then-President and Chief Executive Officer of the General Motors Corporation, the Foundation makes grants in support of original research and education in science, technology, engineering, mathematics, and economics. A full list of the 2019 Fellows is available at the Sloan Foundation website at https://sloan.org/fellowships/2019-Fellows.

Goodwin School 3rd grade visits the Physics Learning Labs

About one mile from the Gant plaza, Goodwin Elementary School teaches some really bright kids. On January 15, 2019, science teacher Nancy Titchen and Goodwin teachers brought the entire 3rd grade class on a field trip to the Physics Learning Labs mock-up studio for some science fun. Students enjoyed a liquid nitrogen show, witnessed quantum effects in superconducting magnetic levitation, experienced mechanics concepts such as angular momentum, and learned about vibrations and the phenomenon mechanical of resonance. The expert hands of a star team of PhD students (Erin Curry and Donal Sheets) and new laboratory technicians (James Jaconetta and Zac Transport) ensured students had a great time and learned some interesting science. Big thanks to the staff and the Goodwin School!