Abstract
We observe a dramatic difference in optical line shapes of a Bose-Einstein condensate and a degenerate Fermi gas by measuring the 1557-nm magnetic dipole transition (8 Hz natural linewidth) in an optical dipole trap. The 15 kHz FWHM condensate line shape is only broadened by mean field interactions, whereas the degenerate Fermi gas line shape is broadened to 75 kHz FWHM due to the effect of Pauli exclusion on the spatial and momentum distributions. The asymmetric optical line shapes are observed in excellent agreement with line shape models for the quantum degenerate gases. For a triplet-singlet -wave scattering length is extracted. The high spectral resolution reveals a doublet in the absorption spectrum of the BEC, and this effect is understood by the presence of a weak optical lattice in which a degeneracy of the lattice recoil and the spectroscopy photon recoil leads to Bragg-like scattering.
- Received 26 August 2016
DOI:https://doi.org/10.1103/PhysRevLett.117.213001
© 2016 American Physical Society
Physics Subject Headings (PhySH)
Erratum
Erratum: Comparison of Spectral Linewidths for Quantum Degenerate Bosons and Fermions [Phys. Rev. Lett. 117, 213001 (2016)]
R. P. M. J. W. Notermans, R. J. Rengelink, and W. Vassen
Phys. Rev. Lett. 118, 069901 (2017)
Synopsis
Atomic Line Shape Carries Mark of Quantum Statistics
Published 16 November 2016
Precision measurements of an atomic transition in cold gases of helium-4 and helium-3 isolate the effects of quantum statistics on the transition’s line shape.
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