Peter Shawhan Awarded 2018 Kirwan Faculty Research and Scholarship Prize

University of Maryland Professor Peter Shawhan received the 2018 Kirwan Faculty Research and Scholarship Prize during the campus’ annual Faculty and Staff Convocation ceremony on September 12, 2018. The prize, which provides a $5,000 stipend, recognizes a faculty member for a highly significant work of research, scholarship or artistic creativity completed within the last three years.

“The Kirwan Prize for 2018 recognizes [Shawhan’s] leadership on a variety of aspects regarding the Laser Interferometer Gravitational-wave Observatory (LIGO) experiment, which provided the first detection of gravitational waves produced by colliding neutron stars, and [his] work in multimessenger astronomy,” said UMD President Wallace D. Loh.

Shawhan also received the USM Board of Regents faculty excellence award earlier this year.

He earned his bachelor’s degree in physics from Washington University in St. Louis, joined the UMD Department of Physics in 2006.

“I came to the University of Maryland because it has an excellent physics department with a lot of different research specialties,” Shawhan said. “I was also familiar with the university because I lived nearby when I was in high school. I participated in the Physics Olympics here and still have a pin from the event.”

Prior to joining UMD, Shawhan was a senior scientist at the California Institute of Technology working on gravitational waves. He first learned about the research field as a graduate student at the University of Chicago, where he earned a Ph.D. in physics in 1999.

“I was studying particle physics at Chicago,” Shawhan said. “But near the end of my Ph.D., my advisor, Bruce Winstein, called me up one evening. He said, ‘[LIGO Co-founder] Kip Thorne is going to be my house tomorrow. Why don’t you come over and talk about LIGO?’ And I got interested.”

Gravitational waves—which Albert Einstein predicted in 1916 as part of the theory of general relativity—are ripples in the fabric of spacetime. In 2015, the LIGO detectors located in Livingston, Louisiana, and Hanford, Washington, detected gravitational waves for the first time. The finding led to the 2017 Nobel Prize in physics for Thorne, Rainer Weiss and Barry Barish.

As data analysis committee chair and a principal investigator of the LIGO Scientific Collaboration (LSC), Shawhan helped the collaboration conclude that the first gravitational waves detected came from the merger of two black holes that produced a single, more massive spinning black hole. In particular, Shawhan helped validate the analysis software that identified the black-hole merger signal a few minutes after the LIGO detectors recorded it. Shawhan also acted as a liaison with collaborating astronomers, performing rapid data analysis and sharing the results with them.

The detection of gravitational waves made it possible to study cosmological events using both gravitational wave detectors and electromagnetic telescopes, which can collect information about events using the entire spectrum of light. Shawhan led the LSC in developing this combined approach, called multimessenger astronomy.

“I first got into multimessenger astronomy in 2007, when a colleague donated telescope time so that some students and I could observe galaxies that our gravitational wave data suggested could be interesting,” Shawhan said. “We realized pretty quickly that it was hard work and we should leave it to professional astronomers, so we switched to collaborating with them.”

To quickly share information with astronomers collaborating with the LSC on multimessenger astronomy studies, Shawhan and his students developed a pipeline to rapidly process and check data from possible gravitational wave events. In addition, Shawhan recruited interested astronomers and helped them strategize about how to best follow up on gravitational wave observations.

Shawhan is particularly proud of the intense multimessenger astronomy campaign that followed the first detection of a merger event between two neutron stars—the dense, collapsed cores that remain after large stars die in a supernova explosion.

On August 17, 2017, gravitational waves from the merger arrived at the twin LIGO detectors. About two seconds later, NASA’s Fermi Gamma-ray Space Telescope detected a gamma-ray burst from the same source. Then, astronomers around the globe directed more than 70 space- and ground-based telescopes toward the event for follow-up observations.

Shawhan called the event one of the best moments of his research career.

“The neutron star merger event was the really spectacular breakthrough that we’d been hoping for,” Shawhan said. “It was just such a rich discovery. The fact that we had so many astronomers lined up to be ready to follow it up really paid off. “

UMD’s long history in the field of gravitational waves provided a boost to his research, Shawhan said. He specifically cited the influence of Physics Professor Emeritus Ho Jung Paik, who developed more sensitive detectors for gravitational waves and helped create the job opportunity that led Shawhan to UMD in the first place.

Today, UMD continues to provide Shawhan with opportunities to further his research.

“The physics department has been very supportive of my work on gravitational waves over the years,” Shawhan said. “It is also great to be able to collaborate with the Department of Astronomy, the Joint Space-Science Institute and NASA’s Goddard Space Flight Center. Through my involvement with them, I’ve become more involved in astrophysics. I’m actually getting involved in some space missions now!”

shawhan regalia pic 2018Provost Rankin, Peter Shawhan and President Loh

Media Relations Contact: Irene Ying, 301-405-5204, This email address is being protected from spambots. You need JavaScript enabled to view it.

Ted Jacobson Named Distinguished University Professor

Ted Jacobson has been named a University of Maryland Distinguished University Professor. This designation is the campus’ highest academic honor, reserved for those whose scholarly achievements “have brought distinction to the University of Maryland.” He was cited for his highly innovative work in black hole thermodynamics, the nature of spacetime, and gravitational physics.

Jacobson received his Ph.D. at the University of Texas and held postdoctoral appointments at the Observatoire de Meudon and Institute Henri Poincaré, Paris; the University of California at Santa Barbara, and Brandeis University before joining UMD as an assistant professor in 1988. He has since held appointments at the University of Bern, the Kavli Institute for Theoretical Physics in Santa Barbara, the Université de Paris VII and the Institute d’Astrophysique in Paris, the University of Utrecht and the Schrödinger Institute of Vienna. Jacobson is a Distinguished Visiting Research Chair at the Perimeter Institute for Theoretical Physics, where he spent part of a 2013-14 sabbatical. He has been a Simons Distinguished Visiting Scholar at the Kavli Institute for Theoretical Physics in Santa Barbara, and in 2015 was co-coordinator of its six-month research program Quantum Gravity Foundations: UV to IR.

Jacobson is a member of the Maryland Center for Fundamental Physics and the Joint Space-Science Institute and a Fellow of the American Association for the Advancement of Science and of the American Physical Society. He was an invited speaker at Stephen Hawking’s 75th birthday conference in 2017, where he spoke on "Hawking radiation, infinite redshifts, and black hole analogues”.

He is a UMD Distinguished Scholar-Teacher, and he co-developed the College Park Scholars Program Science, Discovery and the Universe

His work has been featured in the lay press, including The Economist and He has written for Scientific American, including a cover story, “Echoes of Black Holes.  In 2010, the New York Times published a feature story on gravity and highlighted Jacobson’s 1995 paper “Thermodynamics of Spacetime: The Einstein Equation of State”.  This paper showed that Einstein's equation for the curvature of spacetime derives from thermodynamic principles applied to entanglement entropy of the quantum vacuum. The idea was inspired by black hole thermodynamics, one of his main research foci. His other research interests have included laboratory analogs of black holes, astroparticle and gravitational tests of relativity, and relativistic plasma physics.

Pristine Quantum Light Source Created at the Edge of Silicon Chip

hafezi mittal goldschmidt nature 09 2018 psResearchers configure silicon rings on a chip to emit high-quality photons for use in quantum information processing. Credit: E. Edwards/JQI.

Protected Pathways for Light Offer a way to Streamline Single Photon Production.

The smallest amount of light you can have is one photon, so dim that it’s pretty much invisible to humans. While imperceptible, these tiny blips of energy are useful for carrying quantum information around. Ideally, every quantum courier would be the same, but there isn’t a straightforward way to produce a stream of identical photons. This is particularly challenging when individual photons come from fabricated chips.

Now, researchers at the Joint Quantum Institute (JQI) have demonstrated a new approach that enables different devices to repeatedly emit nearly identical single photons. The team, led by JQI Fellow Mohammad Hafezi, made a silicon chip that guides light around the device’s edge, where it is inherently protected against disruptions. Previously, Hafezi and colleagues showed that this design can reduce the likelihood of optical signal degradation. In a paper published online on Sept. 10 in Nature , the team explains that the same physics which protects the light along the chip’s edge also ensures reliable photon production.

Single photons, which are an example of quantum light, are more than just really dim light. This distinction has a lot to do with where the light comes from. “Pretty much all of the light we encounter in our everyday lives is packed with photons,” says Elizabeth Goldschmidt, a researcher at the US Army Research Laboratory and co-author on the study.  “But unlike a light bulb, there are some sources that actually emit light, one photon at time, and this can only be described by quantum physics,” adds Goldschmidt.

Many researchers are working on building reliable quantum light emitters so that they can isolate and control the quantum properties of single photons. Goldschmidt explains that such light sources will likely be important for future quantum information devices as well as further understanding the mysteries of quantum physics. “Modern communications relies heavily on non-quantum light,” says Goldschmidt. “Similarly, many of us believe that single photons are going to be required for any kind of quantum communication application out there.”

Scientists can generate quantum light using a natural color-changing process that occurs when a beam of light passes through certain materials. In this experiment the team used silicon, a common industrial choice for guiding light, to convert infrared laser light into pairs of different-colored single photons.

They injected light into a chip containing an array of miniscule silicon loops. Under the microscope, the loops look like linked-up glassy racetracks. The light circulates around each loop thousands of times before moving on to a neighboring loop. Stretched out, the light’s path would be several centimeters long, but the loops make it possible to fit the journey in a space that is about 500 times smaller. The relatively long journey is necessary to get many pairs single photons out of the silicon chip.  

Such loop arrays are routinely used as single photon sources, but small differences between chips will cause the photon colors to vary from one device to the next. Even within a single device, random defects in the material may reduce the average photon quality. This is a problem for quantum information applications where researchers need the photons to be as close to identical as possible.

The team circumvented this issue by arranging the loops in a way that always allows the light to travel undisturbed around the edge of the chip, even if fabrication defects are present. This design not only shields the light from disruptions—it  also restricts how single photons form within those edge channels. The loop layout essentially forces each photon pair to be nearly identical to the next, regardless of microscopic differences among the rings. The central part of the chip does not contain protected routes, and so any photons created in those areas are affected by material defects.

The researchers compared their chips to ones without any protected routes. They collected pairs of photons from the different chips, counting the number emitted and noting their color. They observed that their quantum light source reliably produced high quality, single-color photons time and again, whereas the conventional chip’s output was more unpredictable.

“We initially thought that we would need to be more careful with the design, and that the photons would be more sensitive to our chip’s fabrication process,” says Sunil Mittal, a JQI postdoctoral researcher and lead author on the new study. “But, astonishingly, photons generated in these shielded edge channels are always nearly identical, regardless of how bad the chips are.”

Mittal adds that this device has one additional advantage over other single photon sources. “Our chip works at room temperature. I don’t have to cool it down to cryogenic temperatures like other quantum light sources, making it a comparatively very simple setup.”

The team says that this finding could open up a new avenue of research, which unites quantum light with photonic devices having built-in protective features. “Physicists have only recently realized that shielded pathways fundamentally alter the way that photons interact with matter,” says Mittal. “This could have implications for a variety of fields where light-matter interactions play a role, including quantum information science and optoelectronic technology.”

Written by D. Genkina and E. Edwards

Author Affiliations 

Sunil Mittal, Joint Quantum Institute, Institute for Research in Electronics and Applied Physics (IREAP)

Elizabeth Goldschmidt, Joint Quantum Institute and US Army Research Laboratory

Mohammad Hafezi, Joint Quantum Institute, UMD Electrical and Computer Engineering, IREAP and Department of Physics

Reference Publication

"A topological source of quantum light," S. MittalElizabeth A. GoldschmidtMohammad HafeziNature, , (2018)

Research Contact

S. Mittal:  This email address is being protected from spambots. You need JavaScript enabled to view it.

Maissam Barkeshli Receives NSF CAREER Award

Ten University of Maryland faculty members earned Faculty Early Career Development Program (CAREER) awards from the National Science Foundation in the past fiscal year.

The five-year awards are the NSF’s most prestigious in support of junior faculty members who have the potential to serve as academic role models in research and education and lead advances in the mission of their department or organization.