CO.CO.MAT (2005-2017)
Control of Quantum Correlations in Tailored Matter
SFB/TRR 21 - Stuttgart, Ulm, Tübingen
 © Universität Stuttgart | Impressum

Project C1:
Dynamics of collective atom-light states (2005-2008)


We plan to investigate the coherent propagation and phase dynamics of dark polaritons. These novel quasiparticles are mixtures of a photonic and a (dark) collective atomic excitation and can be observed in atomic gases with electromagnetically induced transparency. One of the most striking features of these hybride light-atom states is the presence of extremely slow group velocities ('slow light'). Building upon earlier successful work in both experimental atomic physics and theoretical condensed matter physics, we plan to carry out investigations on the quantum control of such light-matter states in multi-level quantum systems. We plan to apply concepts of low-temperature condensed-matter physics on these well controllable quantum optical systems. In published work on dark polaritons, three atomic levels were relevant and the polaritons represented a coherent superposition of a signal photon and an atom. One focus of the planned works will be polaritons, in which several signal photons couple to an atom. Such excitations can be realized when using multi-level atoms. We here predict a coupling between the photons which is mediated by the atoms. In a first step, we plan to experimentally investigate the modification of photon statistics when breaking up the quasiparticles. We expect correlated photons, as are of interest e.g. in the context of quantum information science. Further, we plan to investigate to what extent theoretical concepts of solid state theory, as (i) the Kondo effect representing an example for correlated non-perturbative multiparticle physics, (ii) the Jahn-Teller effect of a ferroelectric phase transition exhibiting a spontaneous symmetry breaking and (iii) perhaps even vortex formation can be transferred to the discussed quantum optical systems. We are particularly interested in the temporal and spatial phase dynamics of the atomic population interacting with the optical field. Analogous to the described solid state systems, we expect that the chemical potential and phase dynamics of the strongly coupled system of atoms and dipolar radiation field plays a major role in forming a new state of matter. We expect that the dark polaritons can allow for the development of a new field of research located along the frontier between atomic physics and low temperature solid state physics.

Project leaders

Prof. Dr. Martin Weitz, Institut für Angewandte Physik, Universität Bonn

Refs & Publications

L. Karpa, F. Vewinger, and M. Weitz
"Resonance Beating of Light Stored Using Atomic Spinor Polaritons"
Phys. Rev. Lett. 101, 170406 (2008)

U. Vogl and M. Weitz
"Spectroscopy of atomic rubidium at 500-bar buffer gas pressure: Approaching the thermal equilibrium of dressed atom-light states"
Phys. Rev. A 78, 011401 (2008); arXiv: 0704.2151v1 [physics.atom-ph]

L. Karpa and M. Weitz
"Slow light in inhomogeneous and transverse fields"
New J. Phys. 10, 0450158 (2008)

L. Karpa and M. Weitz
"A Stern-Gerlach Experiment for Slow Light"
Nature Physics 2, 332 (2006)