Researchers at NIST have created and imaged a novel pair of coupled quantum dots – tiny islands of confined electric charge that act like interacting artificial atoms. These quantum dots could serve as robust quantum bits (qubits) for quantum computing. Unlike classical bits, qubits can simultaneously take on multiple values, potentially revolutionizing computing.
The team used an ultrasharp scanning tunneling microscope (STM) tip to create the quantum dots in an ultracold sheet of graphene. Applying a magnetic field of 4-8 tesla altered the shape and distribution of the electrons’ orbits, creating two sets of concentric, closely spaced rings within the original well. This is the first time researchers have probed the interior of a coupled quantum dot system so deeply.
The way electrons are shared between the two coupled dots can’t be explained by current quantum dot physics models. Solving this puzzle is important if coupled quantum dots are to be used as qubits in quantum computing.
Keywords: qubits, electrons, graphene, quantum dots, magnetic fields
