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

Abstract

The chameleonic behaviour 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 non-equivalence 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.

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Cited by in corpus (9)

• Chameleonic Theories: A Short Review
• Chameleonic dilaton and conformal transformations
• Species, chameleonic strings and the concept of particle
• Chameleonic equivalence postulate and wave function collapse
• Dilaton stabilization and composite dark matter in the string frame of heterotic-M-theory
• Chameleon fields and solar physics
• The cosmological constant problem in heterotic-M-theory and the orbifold of time
• Chronons in M-theory and F-theory
• Quantum mechanics before the big bang in heterotic-M-theory