Chris Jarzynski, a Distinguished University Professor in the University of 
Christopher Jarzynski. Photo: by Faye Levine Maryland’s Department of Chemistry and Biochemistry, Department of Physics, and Institute for Physical Science and Technology (IPST), is one of three faculty members in the University of Maryland’s College of Computer, Mathematical, and Natural Sciences (CMNS) to received a 2020 Simons Foundation Fellowship. The prestigious fellowships provide support for faculty scientists to extend a one-term, university-sponsored sabbatical into a full year, allowing them to focus solely on advancing fundamental research in mathematics or theoretical physics.
UMD researchers received 2 of the 40 fellowships awarded for mathematics and one of the eight fellowships for theoretical physics. UMD topped the list with the most 2020 Simons Fellows, tied with the University of Michigan, the University of Illinois at Urbana-Champaign and Stony Brook University. UMD’s 2020 Simons Fellows join six other CMNS faculty members who were named Simons Fellows since 2013.
“We are very pleased to congratulate all three of these very accomplished researchers,” said CMNS Dean Amitabh Varshney. “The awarding of this very competitive fellowship to three of our researchers demonstrates UMD’s strength in fundamental research in both mathematics and physics.”
Jarzynski is a statistical physicist and theoretical chemist who models the random motions of atoms and molecules. Working at the boundary between chemistry and physics, Jarzynski studies how the laws of thermodynamics—originally developed to describe the operation of steam engines—apply to complex microscopic systems such as living cells and artificial nanoscale machines.
Jarzkynski is well known for developing an equation to express the second law of thermodynamics for systems at the molecular scale. The equation is known as the Jarzynski equality, which was noted by the Nobel Committee for Physics as an application of the 2018 prize-winning invention, optical tweezers. This research has led to a new method for measuring “free energy”—the energy available to any system to perform useful work—in extremely small systems.
A Fellow of the American Physical Society (APS) and the American Academy of Arts and Sciences, Jarzynski received the APS 2019 Lars Onsager Prize, which recognizes outstanding research in theoretical statistical physics. He was also awarded a Fulbright Fellowship and the Raymond and Beverly Sackler Prize in the Physical Sciences. He serves on the editorial board for the Journal of Statistical Mechanics: Theory and Experiment and is an associate editor for the Journal of Statistical Physics.
Jarzynksi earned his B.A. in physics from Princeton University and his Ph.D. in physics from the University of California, Berkeley. After a postdoctoral appointment at the Institute for Nuclear Theory in Seattle, he spent 10 years at Los Alamos National Laboratory. He has been on the faculty of the University of Maryland since 2006.
During his sabbatical, Jarzynski will be based at UMD but intends to travel to Europe and California for workshops, visiting professorships and collaborations.
UMD's other Simons Fellows were Professor Jacob Bedrossian of the Department of Mathematics and the Center for Scientific Computation and Mathematical Modeling and Professor Leonid Koralov of the Department of Mathematics. Mohammad Hafezi of Physics and ECE was named a 2020 Simons Investigator.
Original story here.
In a hangar-sized laboratory off Paint Branch Drive, Dan Lathrop gives the signal, and what he often calls simply “the experiment” awakens. A huge, steel sphere with tubes and electrical wires snaking across its surface begins a stately, nearly silent rotation inside a towering cage-like structure.
That’s the experiment running at visitor speed, however. When only Lathrop, a Distinguished Scholar-Teacher and professor in physics, and his graduate students are present to gather data, they crank up its 350 horsepower electric motor to spin 80 times faster, until the 3-meter globe encasing 25,000 pounds of liquid sodium blurs out at four revolutions per second.
Professor Dan Lathrop examines the 3-meter steel sphere he uses in simulations of the Earth's "geodynamo." Hidden inside the spinning outer sphere (diagram, below) molten sodium and an even quicker-whirling inner sphere represent the earth's liquid outer core and solid inner core, which create geomagnetism. (Photo by John T. Consoli; diagram by Kolin Behrens)
For safety reasons, in the 11 years since he first switched the experiment on, no lab guest has ever watched it run that fast. Lathrop hasn’t either, exactly. “You can’t see it at full speed,” he said.
If “the experiment” sounds pretty singular, that’s because there’s nothing else like it on the planet. Lathrop, an expert in turbulent flows, envisioned the giant apparatus and several smaller predecessors as a way to simulate and perhaps even predict changes in the Earth’s magnetic field, which originates in its core and helps protect the surface from harmful solar radiation. While the machine has fascinated the geophysics community and generated useful results about planetary magnetic fields, it has never quite fulfilled Lathrop’s hopes. So this year, supported by a recently renewed National Science Foundation grant, he and his lab members will undertake a painstaking process to drain the flammable sodium, dismantle the device, upgrade it and—if the plan works—create a better magnetic model of the Earth.
Our planet has a “g
eodynamo,” a self-generating, self-sustaining magnetic field created by flows in its molten outer core, a layer of mostly iron and nickel more than 3,000 kilometers beneath our feet. Swirling turbulence in the liquid metal, caused by convection and the planet’s rotation, gives rise to electrical currents and magnetic fields that feed on each other.
So far, Lathrop’s experiment needs external current to generate a magnetic field; soon he hopes that will no longer be necessary. Doctoral students Rubén Rojas and Artur Perevalov in physics, along with Heidi Myers in geology and Sarah Burnett in mathematics, have been researching ways to modify a hidden, inner sphere of the device—analogous to Earth’s solid inner core—by adding texture to create swirling, helical flows in the highly conductive liquid sodium, generating electrical currents.
It’s never been tried before, so the results are hard to predict.
“I try not to be a foolish optimist, but you know, you aren’t going to build an experiment like this without a certain amount of optimism that there are interesting things to see,” Lathrop said.
The biggest potential prize would be an ability to predict the “weather” of Earth’s magnetic field, which is constantly in flux. Geologic evidence suggests the poles have reversed hundreds of times—most recently 780,000 years ago—and indeed, the North Pole has been moving from Canada toward Russia with increasing speed in recent years. During such a flip, much of the planet’s surface could have a weaker magnetic shield from solar radiation. (For a preview of what that could be like, look at Mars, which lacks a geodynamo.)
Even now, solar storms do create problems on Earth, damaging satellites and sensitive electronics, said Sara Gibson, a solar physicist at the National Center for Atmospheric Research in Boulder, Colo. For instance, if a massive 1859 solar storm that caused aurora as far south as the tropics hit today, it could fry communications and electrical grids worldwide.
“Dan’s work is really important, because it’s vital to understand the Earth’s magnetic field, which is coupling with what’s coming from the sun, and creating these magnetic impacts,” Gibson said.
Lathrop doesn’t promote his research with disaster scenarios. A pole reversal may not be in the offing at all, and would take more than 1,000 years. But what about scientific curiosity as well as simple prudence concerning a factor that allowed life to arise on earth?
“You think you’d want a solid scientific base knowing, well, how does it work, and how did it get there?” he said. “Where’s it at now? And where’s it going?”
The MURI program complements other DoD basic research efforts that support traditional, single-investigator university research grants. By supporting multidisciplinary teams with larger and longer awards in carefully chosen topics identified for their long-term importance, DoD and the military services boost the potential for significant and sustained advancement of the research in critical areas.
Associate Professor Mohammad Hafezi and JQI postdoctoral researcher Sunil Mittal are participating in a project named “Robust Photonic Materials with High-Order Topological Protection” headed by Gaurav Bahl at the University of Illinois. This work, sponsored by the Office of Naval Research (ONR), will explore techniques for manipulating light in interesting ways—such as restricting it to the corners of a silicon chip. These techniques often offer some protection to the light’s fragile quantum characteristics.
Distinguished University Professor Tom Antonsen and Professor Phil Sprangle are members of a team that will investigate “Fundamental Limits of Controllable Waveform Diversity at High Power.” This effort, sponsored by the Air Force Office of Scientific Research (AFOSR), is led by Edl Schamiloglu at the University of New Mexico.