Philip Kim is Professor of Physics and Professor Applied Physics at Harvard University. Professor Kim is a world leading scientist in the area of materials research. His research area is experimental condensed matter physics with an emphasis on physical properties and applications of nanoscale low-dimensional materials. The focus of Prof. Kim’s group research is the mesoscopic investigation of transport phenomena, particularly, electric, thermal and thermoelectrical properties of low dimensional nanoscale materials.
Presentation Title:Â
Anyon Braiding in Graphene Quantum Hall Interferometer
Presentation Abstract:
The search for anyons, quasiparticles with fractional charge and exotic exchange statistics, has inspired decades of condensed matter research. Moreover, it has been predicted that exchange braiding of these particles, especially non-abelian anyons, can produce topologically protected logic operations that can serve as building blocks for fault-tolerant quantum computing.
Fractional quantum Hall (FQH) effects, in which electrons are confined to two spatial dimensions and subjected to large magnetic fields, have long been predicted to host emergent fractionally charged excitations that obey neither fermionic nor bosonic exchange statistics. Quantum Hall (QH) interferometers allow direct observation of the anyon braiding phase via discrete interference phase jumps as the quasiparticle number changes. FQH Fabry-Pérot (FP) interferometers allow direct measurements of anyon entanglement via the entanglement phase (equivalently two exchanges) of quasiparticles around a confined cavity. By partially backscattering the current at two quantum point contact (QPC) constrictions, the conductance through the FP cavity includes interference terms depending on the phase accrued by quantum Hall (QH) edge-traveling quasiparticles. In this talk, we discuss the observation of the universal anyonic braiding phase in graphene-based quantum Hall interferometers. We demonstrate a new way to characterize the anyon exchange statistics using random telegraph noise that can be controlled by experimental parameters.