Measuring the speed of dark: Detecting dark energy perturbations

Journal Article · Sat May 15 00:00:00 EDT 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.81.103513· OSTI ID:21409702

Putter, Roland de ^[1]; Huterer, Dragan ^[2]; Linder, Eric V ^[1]

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1. Berkeley Lab and University of California, Berkeley, California 94720 (United States)
2. Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan, 48109 (United States)

The nature of dark energy can be probed not only through its equation of state but also through its microphysics, characterized by the sound speed of perturbations to the dark energy density and pressure. As the sound speed drops below the speed of light, dark energy inhomogeneities increase, affecting both cosmic microwave background and matter power spectra. We show that current data can put no significant constraints on the value of the sound speed when dark energy is purely a recent phenomenon, but can begin to show more interesting results for early dark energy models. For example, the best fit model for current data has a slight preference for dynamics [w(a){ne}-1], degrees of freedom distinct from quintessence (c{sub s{ne}}1), and early presence of dark energy [{Omega}{sub de}(a<<1){ne}0]. Future data may open a new window on dark energy by measuring its spatial as well as time variation.

• OSTI ID: 21409702
• Journal Information: Physical Review. D, Particles Fields, Vol. 81, Issue 10; Other Information: DOI: 10.1103/PhysRevD.81.103513; (c) 2010 The American Physical Society; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DEGREES OF FREEDOM
DENSITY
DISTURBANCES
EQUATIONS OF STATE
NONLUMINOUS MATTER
PERTURBATION THEORY
RELICT RADIATION
SOUND WAVES
SPECTRA
VELOCITY
ELECTROMAGNETIC RADIATION
EQUATIONS
MATTER
MICROWAVE RADIATION
PHYSICAL PROPERTIES
RADIATIONS