1998/12/14 by M. Ö. Oktel, M. O. Oktel, Leonid Levitov +1 · 6 citations
Chemistry · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Quantum optics and atomic interactions #Spectroscopy and Laser Applications #cond-mat #physics.atom-ph
paper · pdf · doi:10.1103/physrevlett.83.6
published as Phys. Rev. Lett. 83, 6-9 (1999) · 5 pages, 3 eps figures
arxiv created 1998/12/14 · openalex publication_date 1999/07/05 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Optical excitations in a Bose gas are demonstrated to be sensitive to many-body effects. At low temperature the momentum relaxation is provided by momentum exchange collisions, rather than by elastic collisions. A collective excitation mode forms, which in a nondegenerate gas is manifest in a collision shift and dramatic narrowing of spectral lines. In the Bose-Einstein condensate state, each spectral line splits into two components. The doubling of the optical excitations results from the physics analogous to that of the second sound. We present a theory of the line doubling, and calculate optical absorption spectrum for a uniform density system.