Physics Seminar - Adam Zaman Chaudhry

The study of quantum systems interacting with their environment - so-called open quantum systems - is extremely important from both applied and theoretical points of view. On the applied side, such systems shed light on the practical implementation of various emerging quantum technologies such as quantum computation, metrology and communication. On the theoretical side, the study of open quantum systems has radically altered our understanding of the quantum to classical transition. To study open quantum systems, a variety of techniques have been developed. The most common approach is to use master equations, which generally require making a series of approximations. For example, the system-environment interaction is assumed to be weak, with the system and its environment initially uncorrelated. We have looked at how these commonly ignored initial system-environment correlations can play an important role, especially in the strong system-environment coupling regime. These correlations are also manifested in the geometric phase as well as the estimation of system-environment parameters. We have also derived a master equation that takes into account the initial system-environment correlations. Besides contributing towards a better understanding of open quantum systems, our group has examined the generation of entanglement, as well as quantum state transfer, in a spin chain interacting with its environment. We have shown that suitable control fields can not only effectively remove the detrimental spin chain-environment interaction, but also effectively transform the spin chain in a useful manner.