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Eva-Maria Graefe

Dr Eva-Maria Graefe

Dr Eva-Maria Graefe

Research Fellow

Interests and expertise (Subject groups)

Grants awarded

Development of semiclassical methods for non-Hermitian quantum systems

Scheme: University Research Fellowship

Organisation: Imperial College London

Dates: Apr 2015-Mar 2020

Value: £420,016.58

Summary: Progress in technology is often triggered by paradigm shifts in science that open up unexpected possibilities. The change from Newton's classical physics to quantum physics, for example, ultimately led to technologies such as transistors and lasers. A recent example is the change in the view on "loss" (leakage, friction or dissipation) in many branches of physics. Recent research focuses on the possibilities to modify systems via engineered losses. The systematic application of these ideas relies crucially on a detailed theoretical understanding of the mechanisms and effects of loss on all scales. My research concerns leaky quantum systems. Quantum mechanics traditionally focuses on idealised situations free of losses. For these systems, powerful mathematical methods know as semiclassics can predict quantum behaviour based on classical quantities that are easier to calculate. They are of crucial importance for interpretations and calculations, and ultimately for the design of technological devices. More realistic systems can be described by a generalised "leaky" quantum theory. However, the classical analogue of the effective descriptions typically used on the quantum side is hitherto little investigated. Thus, the powerful framework of semiclassics is likewise unavailable. In my previous work I have identified a classical counterpart of a certain type of leaky quantum systems, known as non-Hermitian quantum theories: a new mathematical structure that is very neat and simple. Using this structure I have started to formulate a semiclassical framework that will be of great use for the description and prediction of new experimental effects and the development of novel technologies.

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