"From cavity QED with quantum gases to optomechanics" Helmut Ritsch

Speaker:
Professor Helmut Ritsch, Universität Innsbruck, Austria

Seminar Title:
From cavity QED with quantum gases to optomechanics

Abstract:
We study the nonlinear coupled dynamics of ultra-cold quantum gases trapped in the light field of high $Q$ optical resonators. In the very low temperature limit the quantum nature of both, light and ultra-cold matter play equally important roles. Using the dynamically generated entanglement and properly designed measurements procedures of the light field allows controlled preparation of many-body atomic states as e.g. atom number squeezed states or Schr{\"o}dinger cat states. If one traps the particles inside the optical cavity, one can create a optical potential, which is a quantized and a dynamical variable itself.
In addition it mediates controllable long range interactions. The self-consistent solution for lightand particles the includes new classes of quantum many-body states as super-solid states and polaron like excitations. In the deep trap limit the collective coupling of the particles and the field can be tailored to reproduce a wide range of optomechanic Hamiltonians with linear, quadratic or even higher order couplings in an environment very close to zero temperature. Similar selfordering dynamics can be observed from atoms trapped in evanescent nanofiber traps.