Final PhD Seminar

Measurement and control of quantum chaotic systems

Ms Jessica Eastman
Department of Quantum Science, RSPE

The emergence of the classical limit from the quantum theory is well understood for regular dynamics. But what happens to the quantum system when the classical limit is chaotic? Quantum chaos is the study of such quantum systems. The emergence of chaos for dissipative systems is interesting because we see a breakdown between the classical and quantum correspondence even when the quantum system is taken to the classical limit. This is a contradiction to what we see in nature. In order to see the emergence of chaos from a dissipative quantum system, we must consider an open quantum system that interacts with an environment. By continuously monitoring a quantum system whose dynamics are chaotic in the classical limit, we are able to observe  chaos. But the choice of measurement strategy itself can determine the degree of chaos. Here I address the effect that continuous measurement has on the emergence of chaos and offer a real time feedback scheme that uses the measurement as a control knob in order to control the degree of chaos. This answers the questions posed about chaos in dissipative systems but also poses some new ones. Is the measurement effect dependent on one particular system or is there a general explanation that can be used for all chaotic systems?

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