Researchers at Washington State University have used a super-cold cloud of atoms that behaves like a single atom to see a phenomenon predicted 60 years ago and witnessed only once since.
The phenomenon takes place in the seemingly otherworldly realm of quantum physics and opens a new experimental path to potentially powerful quantum computing.
Working out of a lab in WSU's Webster Hall, physicist Peter Engels and his colleagues cooled about one million atoms of rubidium to 100 billionths of a degree above absolute zero. There was no colder place in the universe, said Engels, unless someone was doing a similar experiment elsewhere on Earth or on another planet.
At that point, the cluster of atoms formed a Bose-Einstein condensate - a rare physical state predicted by Albert Einstein and Indian theorist Satyendra Nath Bose - after undergoing a phase change similar to a gas becoming a liquid or a liquid becoming a solid. Once the atoms acted in unison, they could be induced to exhibit coherent "superradiant" behavior predicted by Princeton University physicist Robert Dicke in 1954.
"This large group of atoms does not behave like a bunch of balls in a bucket," said Engels. "It behaves as one big super-atom. Therefore it magnifies the effects of quantum mechanics."
Engels' findings appear in the journal Nature Communications. Co-author and collaborator Chuanwei Zhang, a former WSU physicist now at the University of Texas at Dallas, led the theoretical aspects of the work.
Funders include the National Science Foundation, the Army Research Office and the Defense Advanced Research Projects Agency, the cutting-edge research agency known as DARPA.
Researchers using these super-cold dilute gases have created the superradiant state in only one other situation, said Engels, using a far more complicated experiment involving coupling to photon fields. Because the coupling of atoms and photons is usually very weak, their behavior was extremely hard to observe, he said.
"What our colleague Chuanwei Zhang realized is, if you replaced the light with the motion of the particles, you got exactly the same physics," said Engels. Moreover, it's easier to observe. So while their cloud of atoms measures less than half a millimeter across, it is large enough to be photographed and measured. This gives experimenters a key tool for testing assumptions and changes in the atomic realm of quantum physics.
"We have found an implementation of the system that allows us to go in the lab and actually test the predictions of the Dicke model, and some extensions of it as well, in a system that is not nearly as complicated as people always thought it has to be for the Dicke physics," Engels said.
Ordinary physical properties change so dramatically in quantum mechanics that it can seem like a drawing by M.C. Escher. Photons can be both waves and particles. A particle can go through two spaces at the same time and, paradoxically, interfere with itself. Electrons can be oriented up or down at the same time.
This concurrent duality can be exploited by quantum computing. So where a conventional computer uses 1s and 0s to make calculations, the fundamental units of a quantum computer could be 1s and 0s at the same time. As Wired magazine recently noted, "It's a mind-bending, late-night-in-the-dorm-room concept that lets a quantum computer calculate at ridiculously fast speeds."
Peter Engels | Eurek Alert!
Ground-breaking research could challenge underlying principles of physics
23.11.2015 | University of Southampton
Quantum Simulation: A Better Understanding of Magnetism
20.11.2015 | Ruprecht-Karls-Universität Heidelberg
Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.
In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...
In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.
Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...
Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a...
AWI researchers’ unique 15-year observation series reveals how sensitive marine ecosystems in polar regions are to change
The warming of arctic waters in the wake of climate change is likely to produce radical changes in the marine habitats of the High North. This is indicated by...
Berkeley Lab researchers develop nanoparticles that can carry therapeutics across the brain blood barrier
Glioblastoma multiforme, a cancer of the brain also known as "octopus tumors" because of the manner in which the cancer cells extend their tendrils into...
17.11.2015 | Event News
21.10.2015 | Event News
20.10.2015 | Event News
24.11.2015 | Trade Fair News
24.11.2015 | Trade Fair News
24.11.2015 | Life Sciences