TY - JOUR
T1 - Cosmological variation of the fine structure constant from an ultralight scalar field
T2 - The effects of mass
AU - Gardner, Carl
PY - 2003
Y1 - 2003
N2 - Cosmological variation of the fine structure constant due to the evolution of a spatially homogeneous ultralight scalar field (m∼H0) during the matter and A dominated eras is analyzed. Agreement of Δ α/α with the value suggested by recent observations of quasar absorption lines is obtained by adjusting a single parameter, the coupling of the scalar field to matter. Asymptotically α(t) in this model goes to a constant value ᾱ ≈α0 in the early radiation and the late A dominated eras. The coupling of the scalar field to (nonrelativistic) matter drives or slightly away from a in the epochs when the density of matter is important. Simultaneous agreement with the more restrictive bounds on the variation |Δα/α| from the Oklo natural fission reactor and from meteorite samples can be achieved if the mass of the scalar field is on the order of 0.5-0.6 HA, where HA = ΩA 1/2H0. Depending on the scalar field mass, a may be slightly smaller or larger than α0 at the times of big bang nucleosynthesis, the emission of the cosmic microwave background, the formation of early solar system meteorites, and the Oklo reactor. The effects on the evolution of α due to nonzero mass for the scalar field are emphasized. An order of magnitude improvement in the laboratory technique could lead to a detection of (α/α)0.
AB - Cosmological variation of the fine structure constant due to the evolution of a spatially homogeneous ultralight scalar field (m∼H0) during the matter and A dominated eras is analyzed. Agreement of Δ α/α with the value suggested by recent observations of quasar absorption lines is obtained by adjusting a single parameter, the coupling of the scalar field to matter. Asymptotically α(t) in this model goes to a constant value ᾱ ≈α0 in the early radiation and the late A dominated eras. The coupling of the scalar field to (nonrelativistic) matter drives or slightly away from a in the epochs when the density of matter is important. Simultaneous agreement with the more restrictive bounds on the variation |Δα/α| from the Oklo natural fission reactor and from meteorite samples can be achieved if the mass of the scalar field is on the order of 0.5-0.6 HA, where HA = ΩA 1/2H0. Depending on the scalar field mass, a may be slightly smaller or larger than α0 at the times of big bang nucleosynthesis, the emission of the cosmic microwave background, the formation of early solar system meteorites, and the Oklo reactor. The effects on the evolution of α due to nonzero mass for the scalar field are emphasized. An order of magnitude improvement in the laboratory technique could lead to a detection of (α/α)0.
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U2 - 10.1103/PhysRevD.68.043513
DO - 10.1103/PhysRevD.68.043513
M3 - Article
AN - SCOPUS:0141433362
VL - 68
JO - Physical review D: Particles and fields
JF - Physical review D: Particles and fields
SN - 1550-7998
IS - 4
M1 - 043513
ER -