Electron fractionalization in condensed matter systems with weak interactions and time-reversal symmetry

Babak H. Seradjeh, UBC

Abstract: It is now well-known that fractional quantum numbers can arise as the collective excitations of a many-body system. The canonical example of such fractionalization is a 2D electron gas placed in a transverse magnetic field in the fractional quantum Hall (FQH) regime. It is understood that the Coulomb interaction between electrons is crucial to stabilize the incompressible FQH ground state. The system is strongly correlated in the sense that its many- body wavefunctions cannot be constructed from the single-particle states of the constituent fundamental degrees of freedom. The questions then naturally arise whether strong correlations, thus defined, or a broken time-reversal symmetry is necessary for fractionalization to happen. I will argue in this talk, by describing two recent theoretical proposals, that the answers to both questions are negative. Some implications of these proposals for topological schemes of quantum computation are briefly discussed.