The dilaton potential from

Font, Anamarı́a; Klein, Matthias; Quevedo, Fernando

doi:10.1016/s0550-3213(01)00202-4

Cited by 5 publications

(3 citation statements)

References 56 publications

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“…(26) of interest to us here, would be, for instance, that of a 'run away' pre big bang type [37] dilaton potential, in the range where the dilaton slowly approaches a constant value asymptotically and with a decaying trend ∂V (Φ)/∂Φ < 0. Interestingly, this situation characterises N=1 globally supersymmetric theories that can be embedded in a supergravity/superstring framework [38]. 10 It is then straightforward to see that, under the above conditions, the higher order terms in (65) have either vanishing contributions to the equations of motion, or are subleading, for sufficiently smallḃ ≪ M 2 Pl , as required in the approach of [2], for our cosmic background solutions in a FLRW space time.…”

Section: Discussionmentioning

confidence: 95%

“…Thus, we see from (39) that the negative value of the ρ gCS is essential for the consistency of the approach, since it is only then that the energy conservation of the total stress energy tensor (13) leads to consistent results, given the positivity of ρ b . From (38) and (39) we then obtain…”

Section: Gravitational-anomaly-induced Inflation Through Running Vacuummentioning

confidence: 99%

“…The 1% discrepancy between (41) and ( 40) is to be expected, according to our previous discussion ( cf. footnote 5, which implies that the result for (38) for ρ gCS should be mulitplied by an uncertainty factor (1 − ξ 3N ), which lies in the range 0.9889 (1 − ξ 3N ) 0.9905). This is perfectly justified when taking into account also theoretical uncertainties in our estimate (14) of the gravitational-anomaly condensate.…”

Section: Gravitational-anomaly-induced Inflation Through Running Vacuummentioning

confidence: 99%

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Quantum anomalies in string-inspired running vacuum universe: Inflation and axion dark matter

2020

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In this letter, we elaborate further on a Cosmological "Running-Vacuum" type model for the Universe, suggested previously by the authors [1,2], within the context of a string-inspired effective theory in the presence of a Kalb-Ramond (KR) gravitational axion field which descends from the antisymmetric tensor of the massless gravitational string multiplet. In the presence of this field, which has anomalous CP violating interactions with the gravitons, primordial gravitational waves induce gravitational anomalies, which in turn are responsible for the appearance of H 2 and H 4 contributions to the vacuum energy density, these terms being characteristic of generic "runningvacuum-model (RVM) type", where H is the Hubble parameter. In this work we prove in detail the appearance of the H 4 terms due to gravitational-anomaly-induced condensates in the energy density of the primordial Universe, which can self-consistently induce inflation, and subsequent exit from it, according to the generic features of RVM. We also argue in favour of the robustness of our results, which were derived within an effective low-energy field theory approach, against Ultra Violet completion of the theory. During the radiation and matter-dominated eras, gravitational anomalies cancel, as required for the consistency of the quantum matter/radiation field theory. However, chiral and QCD-axion-type anomalies survive and have important consequences for both cosmic magnetogenesis and axionic dark matter in the Universe. Finally, the stringy RVM scenario presented here predicts quintessence-like dynamical dark energy for the current Universe, which is compatible with the existing fitting analyses of such model against observations.

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Section: Discussionmentioning

confidence: 95%

Section: Gravitational-anomaly-induced Inflation Through Running Vacuummentioning

confidence: 99%

Section: Gravitational-anomaly-induced Inflation Through Running Vacuummentioning

confidence: 99%

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Quantum anomalies in string-inspired running vacuum universe: Inflation and axion dark matter

2020

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Brane-antibrane inflation in orbifold and orientifold models

Burgess

Martineau

Quevedo

et al. 2002

J. High Energy Phys.

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133

153

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We analyse the cosmological implications of brane-antibrane systems in string-theoretic orbifold and orientifold models. In a class of realistic models, consistency conditions require branes and antibranes to be stuck at different fixed points, and so their mutual attraction generates a potential for one of the radii of the underlying torus or the 4D string dilaton. Assuming that all other moduli have been fixed by string effects, we find that this potential leads naturally to a period of cosmic inflation with the radion or dilaton field as the inflaton. The slow-roll conditions are satisfied more generically than if the branes were free to move within the space. The appearance of tachyon fields at certain points in moduli space indicates the onset of phase transitions to different non-BPS brane systems, providing ways of ending inflation and reheating the corresponding observable brane universe. In each case we find relations between the inflationary parameters and the string scale to get the correct spectrum of density perturbations. In some examples the small numbers required as inputs are no smaller than 0.01, and are the same small quantities which are required to explain the gauge hierarchy.

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SUSY breaking and moduli stabilization from fluxes in gauged 6Dsupergravity

Aghababaie

Burgess

Parameswaran

et al. 2003

J. High Energy Phys.

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128

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We construct the 4D N = 1 supergravity which describes the low-energy limit of 6D supergravity compactified on a sphere with a monopole backgroundà la Salam and Sezgin. This provides a simple setting sharing the main properties of realistic string compactifications such as flat 4D spacetime, chiral fermions and N = 1 supersymmetry as well as Fayet-Iliopoulos terms induced by the GreenSchwarz mechanism. The matter content of the resulting theory is a supersymmetric SO(3) × U(1) gauge model with two chiral multiplets, S and T . The expectation value of T is fixed by the classical potential, and S describes a flat direction to all orders in perturbation theory. We consider possible perturbative corrections to the Kähler potential in inverse powers of Re S and Re T , and find that under certain circumstances, and when taken together with low-energy gaugino condensation, these can lift the degeneracy of the flat direction for Re S. The resulting vacuum breaks supersymmetry at moderately low energies in comparison with the compactification scale, with positive cosmological constant. It is argued that the 6D model might itself be obtained from string compactifications, giving rise to realistic string compactifications on non Ricci flat manifolds. Possible phenomenological and cosmological applications are briefly discussed.

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The dilaton potential from

Cited by 5 publications

References 56 publications

Quantum anomalies in string-inspired running vacuum universe: Inflation and axion dark matter

Quantum anomalies in string-inspired running vacuum universe: Inflation and axion dark matter

Brane-antibrane inflation in orbifold and orientifold models

SUSY breaking and moduli stabilization from fluxes in gauged 6Dsupergravity

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