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12-04 :: April/May 2012
nanotimes News in Brief
Vina Faramarzi, Frédéric Niess, Emilie Moulin, Mounir Maaloum, Jean-François Dayen, Jean-Baptiste Beaufrand, Silvia Zanettini, Bernard Doudin, and Nicolas Giuseppo- ne: Light-triggered Self-construction of Supramolecular Organic Nanowires as Metallic Interconnects, In: Nature Chemistry, April 22, 2012, DOI: 10.1038/NCHEM.1332: http://dx.doi.org/10.1038/NCHEM.1332
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The detector is sensitive to waves with peak heights of a few percent of a proton diameter, levels so quiet that sound can be governed by quantum law rather than classical mechanics, much in the same way as light.
Scientists from Microtechnology and Nanoscience, Chalmers University of Technology (SE), and Paul Drude Institute for Solid State Electronics (PDI), Germany, have demonstrated a new kind of detec- tor for sound at the level of quietness of quantum mechanics. The result offers prospects of a new class of quantum hybrid circuits that mix acoustic elements with electrical ones, and may help illumi- nate new phenomena of quantum physics.
The “quantum microphone” is based on a single electron transistor, that is, a transistor where the current passes one electron at a time. The acoustic waves studied by the research team propagate over the surface of a crystalline microchip, and resem- ble the ripples formed on a pond when a pebble is thrown into it. The wavelength of the sound is a mere 3 micrometers, but the detector is even smaller, and capable of rapidly sensing the acoustic waves as they pass by. On the chip surface, the researchers have fabricated a three-millimeter-long echo chamber, and even though the speed of sound on the crystal is ten times higher than in air, the detector shows how sound pulses reflect back and forth between the walls of the chamber, thereby verifying the acoustic nature of the wave.
“The experiment is done on classical acoustic waves, but it shows that we have everything in place to begin studies of proper quantum-acoustics, and nobody has attempted that before,” says Mar- tin Gustafsson, PhD student and first author of the article.
Apart from the extreme quietness, the pitch of the waves is too high for us to hear: The frequency of almost 1 gigahertz is 21 octaves above one-lined A. The new detector is the most sensitive in the world for such high-frequency sound.
Martin V. Gustafsson, Paulo V. Santos, Göran Johans- son, Per Delsing: Local probing of propagating acoustic waves in a gigahertz echo chamber, In: Nature Physics, Martin V. Gustafsson, Paulo V. Santos, Göran Johansson, Per Delsing: Local probing of propagating acoustic waves in a gigahertz echo chamber, In: Nature Physics, Vol. 8(2012), No 4, April 2012, Pages 338-343, DOI:10.1038/ nphys2217: