Researchers control electron spin in quest for quantum computing

In quantum physics, a particle's 'spin' refers to its intrinsic angular momentum, which can be controlled so that it is aligned with one of two directions – 'up' or 'down'. This is usually defined by applying a magnetic field to orientate the electron, but this can be distorted by the natural magnetic environment around the electron. Looking to overcome this, the team claim to have used the magnetic field to a natural advantage, allowing the electron to be held in place. This is an important development in the quest to control quantum systems. Dr Mete Atatüre, a researcher at St John's College, Cambridge, who led part of the new study, said: "In order to perform reliable measurements, we constantly have to fight against this fluctuating magnetic environment. In fact, most research is about trying to keep electrons detached or isolated from it. What is unique about this experiment is that we did the opposite and used this environment as a resource. We created a quantum state that wouldn't be accessible if the magnetic field wasn't there." The electron was trapped inside a self-assembled 'quantum dot' made from a 10nm thick indium arsenide droplet, surrounded by gallium arsenide. The electron was then targeted with two separate lasers; one tuned to excite the "up" spin state, the other to excite the "down" state.