Scientists have a new way to edge around a difficult problem in quantum physics, now that a research team from the National Institute of Standards and Technology (NIST) and University of Maryland's Joint Quantum Institute (JQI) have proved* their recent theory about how particles of light flow within a novel device they built.
While the problem itselfhow to find an easier way to study the quantum Hall effectmay be unfamiliar to many, the team's solution could help computer designers use light instead of electricity to carry information in computer circuits, potentially leading to vast improvements in efficiency.
The quantum Hall effect is observed when there is a magnetic field perpendicular to a flat wire that has electrons flowing through it. The field pushes the electrons over to one side of the wire, so their flow is concentrated along its edge. Although a fairly exotic piece of physics, the quantum Hall effect already has been applied to make better standards for electrical conductance. But the effect is hard to study because measuring it requires stringent lab conditions, including extremely low temperatures and samples of exceptional purity.
The team looked for a way around these issues, and in 2011 they found** a potential, albeit theoretical, answer: Build a model system in which particles of light behave exactly like electrons do when subjected to the quantum Hall effect, and study that system instead.
"We knew building an analogous system that uses photons would have additional advantages," says NIST physicist Mohammad Hafezi. "Light can carry much more information than electricity, so working with a photon-based system also could help us design computer components that use light."
To test their theory, the team built an array of tiny, nearly flat silicon rings atop an oxide surface. Beaming photons of the right wavelength at one of the rings makes these photons loop around the ring many times. The ringswh
|Contact: Chad Boutin|
National Institute of Standards and Technology (NIST)