With all the hype surrounding the Large Hadron Collider, it's easy to forget that there are lots of other puzzles in physics still being tackled every day.
The Kondo effect, one of the few examples in physics where many particles collectively behave as one object (a single quantum-mechanical body), has intrigued scientists around the world for decades.
When a single magnetic atom is located inside a metal, the free electrons of the metal 'screen' the atom. That way, a cloud of many electrons around the atom becomes magnetized. Sometimes, if the metal is cooled down to very low temperatures, the atomic spin enters a so-called 'quantum superposition' state. In this state its north-pole points in two opposite directions at the same time. As a result, the entire electron cloud around the spin will also be simultaneously magnetized in two directions.
A team of scientists from the London Centre for Nanotechnology at UCL (University College London) and IBM Almaden Research Center has forged a breakthrough in understanding the Kondo effect and reports on it in Nature Physics.
The researchers, using a technique they initially created in 2007, say it is possible to predict when the Kondo effect will occur, and to understand why. The key turns out to be in the geometry of a magnetic atom's immediate surroundings. By carefully studying how this geometry influences the magnetic moment ('spin') of the atom, the emergence of the Kondo effect can be predicted and understood.
Dr. Cyrus Hirjibehedin, a Lecturer at University College London, said, "This result represents a major advance in our understanding of this fundamental physical phenomenon and could have important consequences for future nanoscale magnetic devices."