Department of Physics & Astronomy
University of New Mexico

CQuIC Seminars

The role of complexity, chaos and non-Markovianity in controlled quantum dynamics

Presented by Pablo Poggi, University of Buenos Aires

In this talk, I will first visit the subject of quantum control in many-body systems and, in particular, discuss the connection between the complexity of a quantum system and its controllability. Using optimal control methods we have derived the control fields required to drive various physical processes in a spin chain. We then studied how the spectral properties of such fields relate to different aspects of the system complexity. We found that the spectral bandwidth of the fields is, quite generally, independent of the system dimension. Conversely, the spectral complexity of such fields does increase with the number of particles. Nevertheless, we found that the regular or chaotic nature of the system does not affect significantly its controllability.
In the second part of the talk, I will focus on driven open quantum systems. In particular, I will tackle the issue of how the presence of a driving field can affect the non-Markovian features of open quantum system dynamics. By studying a paradigmatic model of a two-level system coupled to an structured bath, we show that the driving can greatly enhance the degree of non-Markovianity with respect to the undriven case. This effect is present only when the coupling between system and environment is weak. I will also discuss the role of non-Markovian effects when attempting to control these type of systems.

3:30 pm, Thursday, August 3, 2017
Room 190, Physics & Astronomy
Northeast corner of Lomas and Yale, Albuquerque, New Mexico

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