News: Research

2017

Study examines feeding frenzy behavior in certain worms

August 16, 2017

JFI logo

Mathematical model helps explain animals’ decision-making process.

The C. elegans roundworm sees by eating, sucking in big gulps of bacteria to learn about its surrounding environment. As researchers watched, they noticed an odd pattern marked by “bursts” of eating.

JFI researchers including the Dinner group develeoped a mathematical model to explain such eating bursts. The findings, published Aug. 10 in Proceedings of the National Academy of Sciences, help inform a broader understanding of animals’ feeding behavior and the science of decision-making.

“It’s an interesting model for understanding the processes that underlie how animals decide where and when to eat,” said lead author Monika Scholz, a Howard Hughes Medical Institute international student research fellow with UChicago’s Biophysical Sciences program and now at Princeton University. “For these worms, it’s all about the balance between speed and accuracy.”

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Irvine group measures intertwining vortices in laboratory

August 3, 2017

Irvine research image

Clever experiment documents multi-scale fluid dynamics.

The new findings, published Aug. 3 in Science, are the first to show that helicity maintains a constant value during the flow of viscous fluids. Vortex dynamics have important applications in everyday life; meteorologists, for example, view helicity as a factor that contributes to the formation of supercell tornadoes.

“The fact that we have some measurements for the first time that show helicity can be preserved, especially in the presence of stretching, can translate directly to those efforts,” said William Irvine, an Associate Professor of Physics in the James Franck Institute, who published the findings along with four co-authors.

Simulating helicity in those flows has been difficult because of the widely separated yet interconnecting scales in which they operate. Previous work had been largely theoretical and involved hypothetical, simpler fluids totally lacking in viscosity. Calculations showed that helicity was conserved in these hypothetical fluids, but viscosity emerged as a significant factor in the flow of actual fluids.

“One of the core problems is that you need to sample or measure features of the flow that exist on very different length scales,” said Martin Scheeler, the study’s lead author, who recently completed his Doctorate in Physics in the JFI. The scales range from the diameter of a vortex (approximately 30 centimeters or one foot) to the diameter of its thin core (approximately one milllimeter or three hundredths of an inch).

“You need to measure the flow inside the core as well as the overall shape evolution of that vortex,” Irvine said. “That’s quite a separation.” Irvine characterized Scheeler’s work in overcoming the experimental challenges— simultaneously tracking the fine details of the flow while still measuring the critical larger-scale dynamics—as “a tour de force.”

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Talapin group develops DOLFIN approach to build nanomaterials into electronic devices

July 27, 2017

New method promises easier nanoscale manufacturing.

The new research, published in Science, is expected to make such materials easily available for eventual use in everything from LED displays to cellular phones to photodetectors and solar cells. Though nanomaterials are promising for future devices, ways to build them into complex structures have been limited and small-scale.

“This is a step needed to move quantum dots and many other nanomaterials from proof-of-concept experiments to real technology we can use,” said co-author Dmitri Talapin, Professor of Chemistry in the James Franck Institute and Scientist with the Center for Nanoscale Materials at Argonne. “It really expands our horizons.”

The new technique, called DOLFIN, makes different nanomaterials directly into “ink” in a process that bypasses the need to lay down a polymer stencil. Talapin and his team carefully designed chemical coatings for individual particles. These coatings react with light, so if you shine light through a patterned mask, the light will transfer the pattern directly into the layer of nanoparticles below—wiring them into useful devices.

“We found the quality of the patterns was comparable to those made with state-of-the-art techniques,” said lead author Yuanyuan Wang, postdoctoral researcher in the Talapin group. “It can be used with a wide range of materials, including semiconductors, metals, oxides or magnetic materials—all commonly used in electronics manufacturing.”

The team is working toward commercializing the DOLFIN technology in partnership with UChicago’s Polsky Center for Entrepreneurship and Innovation.

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Chin group settle debate over how exotic quantum particles form

June 22, 2017

Cheng Chin

Implications for universality.

New research by physicists at the University of Chicago settles a longstanding disagreement over the formation of exotic quantum particles known as Efimov molecules. The findings, published last month in Nature Physics, address differences between how theorists say Efimov molecules should form and the way researchers say they did form in experiments. The study found that the simple picture scientists formulated based on almost 10 years of experimentation had it wrong—a result that has implications for understanding how the first complex molecules formed in the early universe and how complex materials came into being.

“I have to say that I am surprised,” Chin said. “This was an experiment where I did not anticipate the result before we got the data.”

The data came from extremely sensitive experiments done with cesium and lithium atoms using techniques devised by Jacob Johansen, previously a graduate student in Chin’s lab who is now a postdoctoral fellow at Northwestern University. Krutik Patel, a graduate student at UChicago, and Brian DeSalvo, a postdoctoral researcher at UChicago, also contributed to the work.

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New method uses heat flow to levitate variety of objects

February 15, 2017

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Undergraduates in Chin group lead breakthrough work.

Third-year Frankie Fung and fourth-year Mykhaylo Usatyuk led a team of UChicago researchers who demonstrated how to levitate a variety of objects—ceramic and polyethylene spheres, glass bubbles, ice particles, lint strands and thistle seeds—between a warm plate and a cold plate in a vacuum chamber.

“They made lots of intriguing observations that blew my mind,” said Cheng Chin, professor of physics, whose ultracold lab in the Gordon Center for Integrative Science was home to the experiments.

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New SPIFF method improves accuracy of imaging systems

February 4, 2017

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Collaborative work by the Dinner, Rice, and Scherer groups

The newly developed SPIFF (single-pixel interior filling function) method provides a way to detect and correct systematic errors in data and image analysis used in many areas of science and engineering.

“Anyone working with imaging data on tiny objects — or objects that appear tiny — who wants to determine and track their positions in time and space will benefit from the single-pixel interior filling function method,” said co-principal investigator Norbert Scherer.

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2016

Chin group confirms theory describing principles of phase transitions

November 3, 2016

Chin research image

Ultracold atoms unveil a universal symmetry of systems crossing continuous phase transitions.

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New Device Steps Toward Isolating Single Electrons for Quantum Computing

May 19, 2016

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The Schuster Group has integrated trapped electrons with superconducting quantum circuits.

“A key aspect of this experiment is that we have integrated trapped electrons with more well-developed superconducting quantum circuits,” said graduate student Ge Yang, lead author of the Physical Review X paper that reported the group’s findings. The team captured the electrons by coaxing them to float above the surface of liquid helium at extremely low temperatures.

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