Chameleonic dilaton, nonequivalent frames, and the cosmological constant problem in quantum string theory

Journal Article · Sun Aug 15 00:00:00 EDT 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.82.044006· OSTI ID:21420943

Zanzi, Andrea ^[1]

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1. Via Pioppa 261, 44123 Pontegradella, Ferrara (Italy)

The chameleonic behavior of the string theory dilaton is suggested. Some of the possible consequences of the chameleonic string dilaton are analyzed in detail. In particular, (1) we suggest a new stringy solution to the cosmological constant problem and (2) we point out the nonequivalence of different conformal frames at the quantum level. In order to obtain these results, we start taking into account the (strong coupling) string loop expansion in the string frame (S-frame), therefore the so-called form factors are present in the effective action. The correct dark energy scale is recovered in the Einstein frame (E-frame) without unnatural fine-tunings and this result is robust against all quantum corrections, granted that we assume a proper structure of the S-frame form factors in the strong coupling regime. At this stage, the possibility still exists that a certain amount of fine-tuning may be required to satisfy some phenomenological constraints. Moreover in the E-frame, in our proposal, all the interactions are switched off on cosmological length scales (i.e., the theory is IR-free), while higher derivative gravitational terms might be present locally (on short distances) and it remains to be seen whether these facts clash with phenomenology. A detailed phenomenological analysis is definitely necessary to clarify these points.

• OSTI ID: 21420943
• Journal Information: Physical Review. D, Particles Fields, Vol. 82, Issue 4; Other Information: DOI: 10.1103/PhysRevD.82.044006; (c) 2010 American Institute of Physics; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CORRECTIONS
COSMOLOGICAL CONSTANT
EXPANSION
FORM FACTORS
INTERACTIONS
MATHEMATICAL SOLUTIONS
NONLUMINOUS MATTER
STRING THEORY
STRONG-COUPLING MODEL
DIMENSIONLESS NUMBERS
MATHEMATICAL MODELS
MATTER
M-THEORY
PARTICLE MODELS
PARTICLE PROPERTIES