NBIA/QDev Seminar: Silvia Viola Kusminskiy – University of Copenhagen

NBIA/QDev Seminar: Silvia Viola Kusminskiy

Adiabatic reaction forces in mesoscopic systems: a scattering matrix approach

Nanoelectromechanical systems are characterized by an intimate connection between electronic and mechanical degrees of freedom. Due to the nanoscopic scale, current flowing through the system noticeably impacts the vibrational dynamics of the device, complementing the effect of the vibrational modes on the electronic dynamics. In this talk I describe our recently developed formalism, in which we employ the scattering matrix approach to quantum transport to describe the current-induced forces acting on the mechanical degrees of freedom of an out-of-equilibrium nanoelectromechanical system. These forces control the Langevin dynamics of the mechanical modes.
Specifically, we derive expressions for the (typically nonconservative) mean force, for the (possibly negative) damping force, an effective "Lorentz" force which exists even for time reversal invariant systems, and the fluctuating Langevin force originating from Nyquist and shot noise of the current flow.