Spins and Charges in Low dimensions

Amir Yacoby

Dept. of Physics, Harvard University, Cambridge MA.

The confinement of electrons to low dimension offers rich possibilities for exploring new physics in a controllable environment. In such restricted geometries, electronic excitations often acquire surprising physical properties that are a result of the underlying lattice and the Coulomb interaction among the electrons. In this talk we shall review some of our recent experiments that explore a variety of low dimensional systems of which some of their properties are listed below. Graphene for example is a two dimensional metal consisting of a monolayer of graphite, where the electronic excitations behave as mass-less relativistic particles. Subjecting a conventional but ultra clean two dimensional electron systems to a quantizing magnetic field opens up possibilities to explore novel phases where quasi particles obey non-Abelian statistics. When reducing dimensionality further to one dimension the electronic excitations loose completely their resemblance to regular electrons and properties such as spin and charge become decoupled and charge fractionalizes.