Kieran is interested in the physics of novel effects in mesoscopic systems. His work falls in three broad categories: submicron electronic devices, heat transport in carbon nanotubes and graphene nano-sheets, and two-dimensional electron gases. “Mesoscopic” systems are those in between the regimes of classical and quantum physics, typically less than a micron across. Experimentalists can routinely fashion devices so small that the electrostatic energy of a single electron can control the flow of current, or in which electrons can travel coherently from one side of the device to the other. The theoretical challenges are to understand how the quantum mechanical effects in the microscopic device couple to macroscopic world of voltmeters and ammeters, and how to take advantage of the novel quantum dynamics for new applications.