Category Physics

Experimentation and largest-ever Quantum Simulation of a Disordered system explain Quantum Many-Particle problem

Figure illustrates puddles of localized quasi-condensates found using a quantum Monte Carlo simulation of trapped atoms in a disordered lattice. Individual puddles, consisting of 10-20 particles each, are incoherent relative to each other. The Bose glass is composed of these puddle-like structures. Credit: Ushnish Ray, University of Illinois

Figure illustrates puddles of localized quasi-condensates found using a quantum Monte Carlo simulation of trapped atoms in a disordered lattice. Individual puddles, consisting of 10-20 particles each, are incoherent relative to each other. The Bose glass is composed of these puddle-like structures. Credit: Ushnish Ray, University of Illinois

Using some of the largest supercomputers available, physics researchers from the University of Illinois at Urbana-Champaign have produced one of the largest simulations ever to help explain one of physics most daunting problems. “This result was a fantastic collaboration between theory and experiment,” explained Prof. Brian DeMarco. “One of the grandest and most impactful frontiers of physics is the quantum many-particle problem...

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Tunable Windows for Privacy, Camouflage

(a) Schematic cross-sectional diagram of the device. In the absence of an electric field, the surfaces are relatively smooth, and light passes through without being scattered or refracted. (b) When connected to a high-voltage source, the nanowires locally compress the elastomer, deforming its surface. Since the nanowires are randomly oriented, the resulting deformation diffuses light passing through the device. (c–f) Changes of opacity at the indicated actuation voltage from 0 to 2.2 kV, demonstrating control over the in-line transmittance using electrical potential. The logo and text are located 15 cm behind the circular film. The black rectangles are electrical contacts to the two sides of nanowire electrodes.

(a) Schematic cross-sectional diagram of the device. In the absence of an electric field, the surfaces are relatively smooth, and light passes through without being scattered or refracted. (b) When connected to a high-voltage source, the nanowires locally compress the elastomer, deforming its surface. Since the nanowires are randomly oriented, the resulting deformation diffuses light passing through the device. (c–f) Changes of opacity at the indicated actuation voltage from 0 to 2.2 kV, demonstrating control over the in-line transmittance using electrical potential. The logo and text are located 15 cm behind the circular film. The black rectangles are electrical contacts to the two sides of nanowire electrodes.

Method turns glass from clear to opaque with the flick of a switch...

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Foldable Material can Change Size, Volume and Shape

Analysis of the possible shapes of the extruded cube unit cell.

Analysis of the possible shapes of the extruded cube unit cell.

Imagine a house that could fit in a backpack or a wall that could become a window with the flick of a switch. Harvard researchers have designed a new type of foldable material that is versatile, tunable and self actuated. It can change size, volume and shape; it can fold flat to withstand the weight of an elephant without breaking, and pop right back up to prepare for the next task.

“We’ve designed a three-dimensional, thin-walled structure that can be used to make foldable and reprogrammable objects of arbitrary architecture, whose shape, volume and stiffness can be dramatically altered and continuously tuned and controlled,” said Johannes T. B. Overvelde, graduate student in Bertoldi’s lab.

The structure is inspired by an or...

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Spray-on Coating could Ice-Proof Airplanes, Power Lines, Windshields

Kevin Golovin, a graduate student in MSE at U-M, demonstrates a new rubbery material that can create ice repelling, or "icephobic," coatings on a variety of materials, such as windshields or ship hulls. Photo by: Evan Dougherty

On your car windshield, ice is a nuisance. But on an airplane, a wind turbine, an oil rig or power line, it can be downright dangerous. And removing it with the methods that are available today – usually chemical melting agents or labor-intensive scrapers and hammers – is difficult and expensive work.

That could soon change thanks to a durable, inexpensive ice-repellent coating developed by University of Michigan researchers. Thin, clear and slightly rubbery to the touch, the spray-on formula could make ice slide off equipment, airplanes and car windshields with only the force of gravity or a gentle breeze. This could have major implications in industries like energy, shipping and transportation, where ice is a constant problem in cold climates.

The new coating could also lead to big ener...

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