C3QS2018 Lecture "Semiclassical wave packet dynamics in quantum systems with loss and gain" Eva-Maria Graefe

Title

Semiclassical wave packet dynamics in quantum systems with loss and gain

Speaker

Eva-Maria Graefe, Research Fellow, Imperial College London, UK

Abstract

While traditional quantum mechanics focusses on systems conserving energy and probability, described by Hermitian Hamiltonians, in recent years there has been ever growing interest in the use of non-Hermitian Hamiltonians. These can effectively describe loss and gain in a quantum system. In particular systems with a certain balance of loss and gain, so-called PT-symmetric systems, have attracted considerable attention. The realisation of PT-symmetric quantum dynamics in optical systems has opened up a whole new field of investigations.

In Hermitian systems, the dynamics of wave packets, which for short times reduces to classical dynamics, provide important insights and tools for quantitative simulations of quantum dynamics. Recently a semiclassical limit of non-Hermitian quantum mechanics has been proposed that allows for a similar description of quantum dynamics generated by non-Hermitian Hamiltonians on the grounds of classical phase-space trajectories. In this talk it will be demonstrated that this classical dynamics can describe the main features of the propagation of optical beams in the presence of gain and loss. We consider two main applications, the propagation of Gaussian beams in a multi-mode wave guide with gain and loss, and Bloch oscillations in a non-Hermitian tight-binding lattice.

This is a part of the workshop C3QS2018 organized by Quantum Systems Unit.  Everyone from OIST commuity is welcome!