Measuring the speed of sound of quintessence

Joel K. Erickson, R. R. Caldwell, Paul J. Steinhardt, C. Armendariz-Picon, V. Mukhanov

Research output: Contribution to journalArticlepeer-review

107 Scopus citations


The measurement of the speed of sound of quintessence, a time-varying energy component describing the accelerated expansion of the universe, was discussed. It was shown that if the quintessence density was at least 1% of the critical density at the surface of last scattering, the cosmic microwave background (CMB) anisotropy distinguished between models whose sound was near the speed of light versus near zero. The results suggested that CMB could be useful in distinguishing competing candidates for dark energy.

Original languageEnglish (US)
Article number121301
Pages (from-to)1213011-1213014
Number of pages4
JournalPhysical Review Letters
Issue number12
StatePublished - Mar 25 2002

ASJC Scopus subject areas

  • General Physics and Astronomy


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