Studying Disorder in Quantum Systems with LasersCategory: Science & Technology
Posted: July 26, 2012 05:25PM
It is interesting to see how obsessed some people can be with order. Trying to make sure certain things are in certain places and then building a system or habit around this order, which is abruptly stopped when something it out of place. The truth though is that much of reality not only is disordered, but only functions as well as it does because of the disorder. Copper wiring, for example, conducts electricity better when there are some impurities. Now researchers at the Joint Quantum Institute are Studying disorder in quantum coherence, and their findings may impact research into superconductors.
Studying disorder is not very easy because you have to somehow control and quantify it. For a large-scale system, this may not be as bad, but for a quantum system on the scale of nanometers, things get tricky. To emulate superconductors, the researchers used a lattice of laser beams to hold rubidium atoms in a specific structure that caused them to enter a single quantum state. By introducing speckle to the laser trap, the lattice is disrupted and creates what is analogous to an impurity within a material. To then measure the disorder, the researchers carefully spilt the disk of trapped atoms in two. These disks were then released from the lasers and allowed to collide, producing an interference pattern that indicates the amount of disorder.
The findings of this study cannot be fully understood right now, sadly, because there is no theory to predict any of the outcomes. However, the researchers have shown that they are indeed able to emulate the high temperature superconductors with this technique. As impurities within these superconductors are already known to improve their conductivity, the ability to study that disorder may lead to improved superconductors in the future.