Physics / Fizik

Permanent URI for this collectionhttps://hdl.handle.net/11147/6

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Author: search.filters.author.Azri, HemzaInstitution Author: search.filters.institutionAuthor.Demir, Durmuş Ali

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Now showing 1 - 2 of 2
  • Article
    Citation - WoS: 26
    Citation - Scopus: 26
    Induced Affine Inflation
    (American Physical Society, 2018) Azri, Hemza; Demir, Durmuş Ali
    Induced gravity, metrical gravity in which gravitational constant arises from vacuum expectation value of a heavy scalar, is known to suffer from Jordan frame vs Einstein frame ambiguity, especially in inflationary dynamics. Induced gravity in affine geometry, as we show here, leads to an emergent metric and gravity scale, with no Einstein-Jordan ambiguity. While gravity is induced by the vacuum expectation value of the scalar field, nonzero vacuum energy facilitates generation of the metric. Our analysis shows that induced gravity results in a relatively large tensor-to-scalar ratio in both metrical and affine gravity setups. However, the fact remains that the induced affine gravity provides an ambiguity-free framework.
  • Article
    Citation - WoS: 47
    Citation - Scopus: 42
    Affine Inflation
    (American Physical Society, 2017) Azri, Hemza; Demir, Durmuş Ali
    Affine gravity, a gravity theory based on affine connection with no notion of metric, supports scalar field dynamics only if scalar fields have nonvanishing potential. The nonvanishing vacuum energy ensures that the cosmological constant is nonvanishing. It also ensures that the energy-momentum tensor of vacuum gives the dynamically generated metric tensor. We construct this affine setup and study primordial inflation in it. We study inflationary dynamics in affine gravity and general relativity, comparatively. We show that nonminimally coupled inflaton dynamics can be transformed into minimally coupled ones with a modified potential. We also show that there is one unique frame in affine gravity, as opposed to the Einstein and Jordan frames in general relativity. Future observations with higher accuracy may be able to test affine gravity.