Lecturer: Prof. Shimshon Bar-Ad
Affiliation: Tel-Aviv University
Abstract:
The hydrodynamic representation of the nonlinear Schrödinger equation allows one to describe coherent light propagation in a Kerr-type nonlinear medium as a quantum fluid of interacting photons. This idea has given rise to experimental demonstrations of “dispersive shock waves”, and to proposals for creating optical analogue event horizons, based on Unruh’s prediction (1981) that a thermal spectrum of sound waves would be emitted from the sonic horizon in transonic fluid flow, in analogy to the emission of Hawking radiation from the event horizon of a black-hole. Most of the relevant experiments carried out to date involve nonlocal, usually thermal nonlinear media. In such media, however, shock waves turn into caustics, and the non-locality diminishes the prospects of observing quantum fluctuations and their classical counterparts. I will discuss these issues in detail and present our short-term plans for constructing a quasi-stationary analogue event horizon, using rubidium vapor as a local nonlinear medium, and our long-term plans to tackle the difficult challenge of observing quantum fluctuations in this construct.