Black Hole-like Behavior is Observed in Cold Atom Nanotube Setup
Since I’m on a reading-up-on-nanoparticles streak…
Researchers at Harvard University have documented the occurrence of conditions similar to those of a black hole event horizon by simply using carbon nanotubes and cold atoms. The experiment, which is the first to discover these behaviors on an atomic scale, is described in the current issue of the journal of the American Physical Society, Physical Review Letters. (A synopsis is available at http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.104.133002)
The researchers took a carbon nanotube, suspended it in a silicon structure and then charged it to a couple of hundred volts. A cloud of millions of single atoms was then laser-cooled to just 200 microKelvins (barely above absolute zero) and launched towards the carbon nanotube. Matter tends to demonstrate some interesting behaviors when temperatures near absolute zero (take Bose-Einstein condensates, for instance), and one of the benefits of cooling the atoms to such a low temperature is that it exponentially slows their movements down, allowing for easier detection and manipulation of individual atoms.
By aiming the cloud of super-cold atoms towards the nanotube, the ionization of the tube attracts the few atoms that come within a close enough distance with an irresistible pull, much in the same way that a black hole does with nearby stars, light and gas. The atoms begin to orbit the tube at a high speed of 2700 MPH, raising the kinetic energy of the atoms to a high enough level that the atom splits into an electron and ion pair. These mates continue their orbiting dance until the electron is “sucked into” the nanotube through a process known as quantum tunneling, a process that not only defies a simple explanation but also the laws of classical mechanics and Newtonian physics. Without it’s electron mate to keep it in orbit, the ion is repulsed away at a speed of 59,000 MPH.
Launched laser-cooled atoms are captured by a single, suspended, single-wall carbon nanotube charged to hundreds of volts. A captured atom spirals towards the nanotube (white path) and reaches the environs of the tube surface, where its valence electron (yellow) tunnels into the tube. The resulting ion (purple) is ejected and detected, and the dynamics at the nanoscale are sensitively probed. (Credit: Anne Goodsell and Tommi Hakala/Harvard University)
This experiment opens up new possibilities for topics of study in the fields of physics, quantum mechanics and cold atoms in particular. Scientists may be able to find new ways to unlock the darkest secrets of the universe and gain a greater understanding of the fundamentals of matter without having to resort to expensive and prohibitive methods such as the use of particle accelerators.
Launched laser-cooled atoms are captured by a single, suspended, single-wall carbon nanotube charged to hundreds of volts. A captured atom spirals towards the nanotube (white path) and reaches the environs of the tube surface, where its valence electron (yellow) tunnels into the tube. The resulting ion (purple) is ejected and detected, and the dynamics at the nanoscale are sensitively probed. (Credit: Anne Goodsell and Tommi Hakala/Harvard University)