Scale-invariant quadratic gravity and inflation in the Palatini formalism

Gialamas, Ioannis D.; Καράμ, Αλέξανδρος; Παππάς, Θωμάς; Spanos, Vassilis C.

doi:10.1103/physrevd.104.023521

Cited by 47 publications

(32 citation statements)

References 213 publications

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“…• Chapter 8, is based on [4,5]. In this we study Scale-invariant models of inflation with the presence of quadratic in curvature terms in the usual Einstein-Hilbert action, again in the context of Palatini formulation of gravity.…”

Section: Prefacementioning

confidence: 99%

“…Additional papers and conference proceedings: During the last four years I have also participated in writing the papers [6][7][8] which did not fit within the story line of this thesis and are not included. Furthermore, the conference proceedings [9], based on [4,5], have been presented in HEP-2021 and the [10], based on [1,2], have been presented in BSM-2021.…”

Section: Prefacementioning

confidence: 99%

“…Η δυναμική παραγωγή της κλίμακας Planck επιτυγχάνεται συνήθως σε θεωρίες αναλλοίωτης κλίμακας [4,5,9, στις οποίες το ῾῾τρέξιμο᾿᾿ της τεταρτικής σταθεράς σύζευξης του ίνφλατον προκαλεί ένα σπάσιμο συμμετρίας αλά Coleman-Weinberg. Η αναλλοιώτητα κλίμακας υπαινίσσεται ότι η Λανκρανζιανή μιας θεωρίας δεν πρέπει να περιέχει παραμέτρους μάζας επί τούτου.…”

Section: Prefaceunclassified

“…We will proceed computing the T = 0 and T = 0 parts separately, starting from Σ (T ) . The contribution to the fermion selfenergy due to vector-boson loop graph is 4 − iΣ…”

Section: Fermion Selfenergymentioning

confidence: 99%

“…Dynamical generation of the Planck scale is usually achieved in scale-invariant theories [4,5,9,, in which the running of the inflaton quartic coupling induces symmetry breaking à la Coleman-Weinberg. Scale invariance postulates that the Lagrangian of a theory should not contain any ad hoc mass parameters.…”

Section: Introductionmentioning

confidence: 99%

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Cosmological implications of theories beyond the standard model of particle physics

Gialamas¹,

Γιαλαμάς²

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Στο πρώτο μέρος της διατριβής, υπολογίζεται ο ρυθμός παραγωγής βαρυτίνων, μέσω της θερμικής ιδιοενέργειας σε επίπεδο ενός-βρόχου. Επίσης, παρέχουμε μια εύχρηστη φόρμουλα για τον ρυθμό παραγωγής και τη θερμική αφθονία των βαρυτίνων, σε συνάρτηση με τη θερμοκρασία αναθέρμανσης του Σύμπαντος. Η αφθονία των βαρυτίνων συγκρίνεται με την παρατηρούμενη σκοτεινή ύλη. Στο δεύτερο μέρος της διατριβής θεωρούμε την τετραγωνική βαρύτητα σε Palatini φορμαλισμό υποθέτοντας την ύπαρξη βαθμωτών πεδίων συνδεδεμένων με τη βαρύτητα. Όταν τα βαθμωτά πεδία αναπτύξουν την αναμενόμενη τιμή του κενού τους η κλίμακα Planck δημιουργείται δυναμικά. Το αποτέλεσμα των τετραγωνικών όρων καμπυλότητας είναι η μείωση της τιμής του λόγου τανυστή-βαθμωτού r. Οι πληθωριστικές προβλέψεις όλων των υπό εξέταση μοντέλων διαπιστώνεται ότι συμφωνούν με τα τελευταία παρατηρητικά δεδομένα που έχουν τεθεί από τη συνεργασία Planck για ένα ευρύ φάσμα των εμπλεκόμενων παραμέτρων.

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Section: Prefacementioning

confidence: 99%

Section: Prefacementioning

confidence: 99%

Section: Prefaceunclassified

“…We will proceed computing the T = 0 and T = 0 parts separately, starting from Σ (T ) . The contribution to the fermion selfenergy due to vector-boson loop graph is 4 − iΣ…”

Section: Fermion Selfenergymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cosmological implications of theories beyond the standard model of particle physics

Gialamas¹,

Γιαλαμάς²

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Cosmology of Metric‐Affine R+βR2$R + \beta R^2$ Gravity with Pure Shear Hypermomentum

Iosifidis,

Myrzakulov,

Ravera

2023

Fortschritte der Physik

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In this paper, cosmological aspects of metric‐affine gravity with hyperfluid are studied. The equations of motion of the theory are obtained by varying the action with respect to the metric and the independent connection. Subsequently, considering a Friedmann‐Lemaître‐Robertson‐Walker background, the modified Friedmann equations in the presence of a perfect cosmological hyperfluid is derived. Especially, a particular case in which is focused, considering purely shear hypermomentum and finding exact solutions in the weak coupling limit.

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Gravitational Coleman-Weinberg mechanism

Álvarez-Luna

Calle-Leal

Cembranos

et al. 2023

J. High Energ. Phys.

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The Coleman-Weinberg mechanism provides a procedure by which a scalar field, which initially has no mass parameters, acquires a mass due to the anomalous nature of scale symmetry. Loop corrections trigger a spontaneous symmetry breaking and the appearance of a non-trivial vacuum. We first review the basic example of the Coleman-Weinberg mechanism, scalar Quantum Electrodynamics, in a perturbative regime where the scalar particle becomes massive through photon loops. We then present the main results of this article, what we name the gravitational Coleman-Weinberg mechanism: we analyse the same effect in a gravitational theory without explicit energy scales at tree-level. Finally, we also study the mechanism for two scalar fields in the mentioned gravitational theory. We will derive the gravitational Coleman-Weinberg potentials, analyse the parameter space where we have a symmetry breaking, and obtain the value of the corresponding scalar masses.

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Scale-invariant quadratic gravity and inflation in the Palatini formalism

Cited by 47 publications

References 213 publications

Cosmological implications of theories beyond the standard model of particle physics

Cosmological implications of theories beyond the standard model of particle physics

Cosmology of Metric‐Affine R+βR2$R + \beta R^2$ Gravity with Pure Shear Hypermomentum

Gravitational Coleman-Weinberg mechanism

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