Everyone after Einstein knew that matter is really waves, that electrons for instance have a wavelength that causes quantum properties to emerge when they are confined is a space smaller than their wavelength. Now researchers are proposing to amplify, filter and otherwise manipulate such matter waves using a meta-material-based device. Called a Schrödinger's hat, it performs signal processing on matter waves while remaining invisible to outsiders : R. Colin Johnson
A matter wave hitting a Schrodinger's hat. The wave inside the container is magnified. Outside, the waves wrap as if they had never encountered any obstacle. Credit: G. Uhlmann, U. of Washington
Here is what the University of Washington says about matter waves: Invisibility, once the subject of magic or legend, is slowly becoming reality. Over the past five years mathematicians and other scientists have been working on devices that enable invisibility cloaks – perhaps not yet concealing Harry Potter, but at least shielding small objects from detection by microwaves or sound waves.
A University of Washington mathematician is part of an international team working to understand invisibility and extend its possible applications. The group has now devised an amplifier that can boost light, sound or other waves while hiding them inside an invisible container.
As a first application, the researchers propose manipulating matter waves, which are the mathematical description of particles in quantum mechanics. The researchers envision building a quantum microscope that could capture quantum waves, the waves of the nanoworld. A quantum microscope could, for example, be used to monitor electronic processes on computer chips.
The authors dubbed their system "Schrödinger's hat," referring to the famed Schrödinger's cat in quantum mechanics. The name is also a nod to the ability to create something from what appears to be nothing.
Gunther Uhlmann, who is on leave at the University of California, Irvine, has been working on invisibility with fellow mathematicians Allan Greenleaf at the University of Rochester, Yaroslav Kurylev at University College London in the U.K., and Matti Lassas at the University of Helsinki in Finland, all of whom are co-authors on the new paper.
The team helped develop the original mathematics to formulate cloaks, which must be realized using a class of engineered materials, dubbed metamaterials, that bend waves so that it appears as if there was no object in their path. The international team in 2007 devised wormholes in which waves disappear in one place and pop up somewhere else.
For this paper, they teamed up with co-author Ulf Leonhardt, a physicist at the University of St. Andrews in Scotland and author on one of the first papers on invisibility.
Recent progress suggests that a Schrodinger’s hat could, in fact, be built for some types of waves.
The research was funded by the National Science Foundation in the U.S., the Engineering and Physical Sciences Research Council and the Royal Society in the U.K., and the Academy of Finland.