The main subject is the theoretical study of quantum transport phenomena such as quantum Hall effect in two dimensional systems in high magnetic fields and electron localization in disordered system. Another is the theoretical study of electronic properties of low dimensional systems, in particular, quantum wells, superlattices, quantum wires, and dots. Some of the current topics includes ballistic conduction across quantum point contacts in magnetic fields, conductance fluctuations and localization in quantum wires,
cross over of the quantum Hall effect from two to one dimensions, phonons and electronphonon interactions in superlattices, high-electric-field transport in high magnetic fields, and electronic, optical, and transport properties of carbon nanotubes and graphene.