Dvira Segal

LM 420D - Lash Miller Chemical Laboratories, 80 St. George Street, Toronto, ON, M5S 3H6



Department of Physics

Fields of Study

Areas of Interest

My research deals with theoretical and computational aspects of the dynamics of out-of-equilibrium, many-body, quantum dissipative systems, with implications both in basic science, and for device applications. Some of the ongoing projects are:

  1. Spin dynamics in non-equilibrium systems: Magnetic effects in the nanoscale are interesting both from the fundamental point of view, and practically, for designing efficient nanoscale spin-electronic devices. In order to elucidate on the fundamental aspects of the non-equilibirum dynamics, we focus on a simple magnetic impurity system, a variant of the Kondo model, driven out-of-equilibirum by an external bias voltage. We use perturbative calculations, as well as exact numerical techniques (path integrals, numerical renormalization group), and study the transient and the long time dynamics of the system. This project helps us pinpoint the fundamentally unique dissipation processes taking place in nonequilibrium many-body systems, in comparison to their equilibrium counterparts.
  2. Heat transfer in molecular junctions: In recent years there has been a growing interest in nanomechanics of quantum systems. Our goal is to understand the classical and quantal aspects of heat transfer in low dimensional systems. Some of the questions we ask are: What are the mechanisms of heat transfer in the nanoscale? How does the thermal conductance depend on the internal structure, temperature and length? What is the effect of dimensionality? What is the role of quantum coherent effects? Ultimately, we would like to consider feasible methods for controlling and managing heat flow at the molecular level. Our work is done at different levels: (i) We develop first principle formulations of phononic heat transfer at the nanoscale. (ii) We construct simple "toy" models that capture the basic factors affecting energy transport in molecular junctions. (iii) We use molecular dynamics simulations to realistically describe vibrational energy transfer between interfaces.

Other areas of interest include electron transport in molecular systems, thermodynamics of quantum heat engines, thermoelectric and thermionic nanoscale devices, and quantum control in dissipative systems.