@phdthesis{Schiefele2011,
  author    = {Schiefele, J{\"u}rgen},
  title     = {Casimir-Polder interaction in second quantization},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-54171},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {The Casimir-Polder interaction between a single neutral atom and a nearby surface, arising from the (quantum and thermal) fluctuations of the electromagnetic field, is a cornerstone of cavity quantum electrodynamics (cQED), and theoretically well established. Recently, Bose-Einstein condensates (BECs) of ultracold atoms have been used to test the predictions of cQED. The purpose of the present thesis is to upgrade single-atom cQED with the many-body theory needed to describe trapped atomic BECs. Tools and methods are developed in a second-quantized picture that treats atom and photon fields on the same footing. We formulate a diagrammatic expansion using correlation functions for both the electromagnetic field and the atomic system. The formalism is applied to investigate, for BECs trapped near surfaces, dispersion interactions of the van der Waals-Casimir-Polder type, and the Bosonic stimulation in spontaneous decay of excited atomic states. We also discuss a phononic Casimir effect, which arises from the quantum fluctuations in an interacting BEC.},
  language  = {en}
}
@article{SchiefeleHenkel2011,
  author    = {Schiefele, Juergen and Henkel, Carsten},
  title     = {Bosonic enhancement of spontaneous emission near an interface},
  series = {Modern physics letters : A, Particles and fields, gravitation, cosmology, nuclear physics},
  volume    = {375},
  journal   = {Modern physics letters : A, Particles and fields, gravitation, cosmology, nuclear physics},
  number    = {3},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0375-9601},
  doi       = {10.1016/j.physleta.2010.11.058},
  pages     = {680 -- 684},
  year      = {2011},
  abstract  = {We show how the spontaneous emission rate of an excited two-level atom placed in a trapped Bose-Einstein condensate of ground-state atoms is enhanced by bosonic stimulation. This stimulation depends on the overlap of the excited matter-wave packet with the macroscopically occupied condensate wave function, and provides a probe of the spatial coherence of the Bose gas. The effect can be used to amplify the distance-dependent decay rate of an excited atom near an interface.},
  language  = {en}
}