On Quantum Tunnelling

Department Colloquia

Speaker: Neil Turok, Perimeter Institute
Date & Time: October 31, 2013 16:00 - 17:00
Location: UBC, Hennings 201
Local Contact: Moshe Rozali
Intended Audience: Undergraduate

One of the most basic but intriguing properties of quantum systems is their ability to `tunnel’ between configurations which are classically disconnected. That is, processes which are classically not just slow, but impossible, become possible. In this talk I will outline a new, elementary approach to quantum tunneling which emphasizes that the dominant classical trajectory is usually complex, i.e., includes an imaginary part rather than being purely real. Through combining the semiclassical approximation with the concepts of post-selection and weak measurement, sharp answers can be given to questions such as ‘how long did the tunneling take’ and ‘where was the particle while it was tunneling?’ Applications of this formalism span a vast range, from experimentally testing the ‘reality of reality’ (!) to making sense of the inflationary multiverse and understanding the Hawking process of black hole evaporation.