Nav: Home

UChicago leads Simons Foundation collaboration to study the physics of glass

July 12, 2016

Sometimes in science, the most mundane phenomena embody the deepest mysteries. For example, glass is made by cooling a liquid rapidly until it solidifies. But when and how does that change occur? When does liquid become solid? Is there a definite transition at all?

The answers to those questions would have implications far beyond understanding the physics of glass, in realms as far flung as biology, computer science and astrophysics. Sidney Nagel, the Stein-Freiler Distinguished Service Professor of Physics at the University of Chicago, hopes to find them.

Nagel leads the Simons Collaboration on Cracking the Glass Problem, a group of 13 scientists from seven European institutions and five other U.S. universities funded by the Simons Foundation through the Collaborations in Mathematics and Physical Sciences program. The collaboration, supported by a $10 million grant from the Simons Foundation, aims to build upon recent theoretical advances to achieve a unified and general understanding of the glass transition.

"This is a problem that has been plaguing physics and chemistry for a long, long time," Nagel said. "People have made inroads. But we now have different techniques, looking from different points of view, which we think will be able to bring things to a point where we'll be able to solve something concretely about this glass transition problem."

The Simons Foundation is well known for supporting discovery-driven science that seeks to better understand theoretical problems of fundamental scientific importance, said Edward "Rocky" Kolb, dean of the Division of the Physical Sciences.

Deceptively complicated

"We are grateful to the Simons Foundation for backing this remarkable team that Sid Nagel has assembled. We need just such a team if we hope to see our way through into exactly what endows the glassy state of matter with its curious properties--a more deceptively complicated problem than one might imagine," Kolb said.

Glass has two properties that make it particularly challenging for theorists. Unlike metals and other crystalline solids, its atoms are not arranged in an orderly periodic lattice; they are a disorderly array. "Physics is not yet very good at understanding things that are disordered," Nagel said.

Second, it is far from what physicists call thermal equilibrium. And physics has a hard time addressing that too, even though scientists are interested in behavior that occurs in systems not in equilibrium, including the folding of proteins, the weather--even the cooling of the universe after the Big Bang. Getting a handle on the way glass forms provides a way to understand these other phenomena, Nagel added.

"Far-from-equilibrium behavior is, to me, the most exciting and deepest question in science today," he said.

Energy landscape

To understand the glass transition from liquid to solid, scientists need to account for every possible state the system could occupy at any moment. It's what scientists call an "energy landscape." If any single particle sits at point A rather than at B, the whole landscape changes because that particle is interacting with all the others in the system. When, as in a forming glass, there are millions of particles, each able to move in three dimensions, the energy landscape becomes rugged. Mathematical description becomes prodigious and an exact solution almost impossible.

Nagel was working on one approach to the problem: examining a simplified case in which the glass was held at absolute zero, so there were no atoms moving. It wasn't applicable to real-world temperatures, but he and his collaborators were able to show a clean and clear transition to a rigid solid. "Pretty far from useful," Nagel said. "But if you know something is exact at some point, you can start at that point and work away from it."

Meanwhile, researchers in Europe were coming at the problem from another angle. They found a clear transition for a theoretical glass in which every particle could exist in an infinite number of dimensions.

Intriguingly, the two very different approaches produced some identical mathematical results in areas where they overlapped. The groups decided to collaborate, working from the two extreme cases toward a realistic picture of what happens in three dimensions at normal temperatures. A third group studying the dynamics of low-temperature liquids helped bring the two approaches together.

Nagel hopes that this work will yield a method that will be useful in other problems, familiar and unknown, with rugged energy landscapes.

"People use energy landscapes in many scientific contexts," Nagel said. "What we have with the glass problem is the progenitor of all landscape pictures. What we're able to do with this very concrete problem is to say some specific things about how to treat a landscape of this kind that is not possible in those other contexts. And you hope that this understanding can be disseminated to other areas which you originally thought were not related at all."
-end-


University of Chicago

Related Physics Articles:

Physics vs. asthma
A research team from the MIPT Center for Molecular Mechanisms of Aging and Age-Related Diseases has collaborated with colleagues from the U.S., Canada, France, and Germany to determine the spatial structure of the CysLT1 receptor.
2D topological physics from shaking a 1D wire
Published in Physical Review X, this new study propose a realistic scheme to observe a 'cold-atomic quantum Hall effect.'
Helping physics teachers who don't know physics
A shortage of high school physics teachers has led to teachers with little-to-no training taking over physics classrooms, reports show.
Physics at the edge
In 2005, condensed matter physicists Charles Kane and Eugene Mele considered the fate of graphene at low temperatures.
Using physics to print living tissue
3D printers can be used to make a variety of useful objects by building up a shape, layer by layer.
When the physics say 'don't follow your nose'
Engineers at Duke University are developing a smart robotic system for sniffing out pollution hotspots and sources of toxic leaks.
The coming of age of plasma physics
The story of the generation of physicists involved in the development of a sustainable energy source, controlled fusion, using a method called magnetic confinement.
Physics: Not everything is where it seems to be
Scientists at TU Wien, the University of Innsbruck and the ÖAW have for the first time demonstrated a wave effect that can lead to measurement errors in the optical position estimation of objects.
'Fudge factors' in physics?
What if your theory to model and predict the electronic structure of atoms isn't accounting for dispersion energy?
Breakthrough in quantum physics
Researchers from Graz University of Technology have described for the first time the dynamics which takes place within a trillionth of a second after photoexcitation of a single atom inside a superfluid helium nanodroplet.
More Physics News and Physics Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.