Výsledky vyhledávání - "A. Emir Gümrükçüoğlu"

Spinning guest fields during inflation: Leftover signatures

Autor: Matteo Fasiello, Emanuela Dimastrogiovanni, A. Emir Gümrükçüoğlu

Publikováno v: Journal of Cosmology and Astroparticle Physics, 2021(11):047. IOP PUBLISHING LTD

We consider the possibility of extra spinning particles during inflation, focussing on the spin-2 case. Our analysis relies on the well-known fully non-linear formulation of interacting spin-2 theories. We explore the parameter space of the correspon

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::db56c27fcd767b8bd8486fed284eaf59
https://research.rug.nl/en/publications/3a4d2ed6-73f3-4046-aaa4-c620761a5800

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Vainshtein Mechanism in Generalised Massive Gravity

Autor: Michael Kenna-Allison, A. Emir Gümrükçüoğlu, Rampei Kimura, Kazuya Koyama

We present a non-linear analysis of perturbations around cosmological solutions in Generalised Massive gravity. This Lorentz invariant theory is an extension of de Rham, Gabadadze, Tolley massive gravity that propagates $5$ degrees of freedom while a

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Cosmic acceleration and growth of structure in massive gravity

Autor: Kazuya Koyama, Michael Kenna-Allison, A. Emir Gümrükçüoğlu

Publikováno v: Kenna-Allison, M, Gumrukcuoglu, A E & Koyama, K 2020, ' Cosmic acceleration and growth of structure in massive gravity ', Physical Review D-Particles, Fields, Gravitation and Cosmology, vol. 102, no. 10, 103524 . https://doi.org/10.1103/PhysRevD.102.103524
Physical Review D

We introduce a cosmological model in the framework of Generalised Massive Gravity. This theory is an extension of non-linear massive gravity with a broken translation symmetry in the St��ckelberg space. In a recent work, we showed the existence o

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https://researchportal.port.ac.uk/ws/files/25133460/PhysRevD.102.103524.pdf

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A larger value for $H_0$ by an evolving gravitational constant

Autor: Matteo Braglia, William T. Emond, A. Emir Gümrükçüoğlu, Kazuya Koyama, Fabio Finelli, Mario Ballardini, Daniela Paoletti

Publikováno v: Physical Review D
Braglia, M, Ballardini, M, Emond, W T, Finelli, F, Gumrukcuoglu, A E, Koyama, K & Paoletti, D 2020, ' A larger value for H 0 by an evolving gravitational constant ', Physical Review D, vol. 101, no. 2, 023529 . https://doi.org/10.1103/PhysRevD.102.023529

We provide further evidence that a massless cosmological scalar field with a non-minimal coupling to the Ricci curvature of the type $M^2_{\rm pl}(1+\xi \sigma^n/M_{\rm pl}^n) $ alleviates the existing tension between local measurements of the Hubble

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fcebc5effba2771e9bda2d98df1a60ac
http://arxiv.org/abs/2004.11161

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Massive gravity with non-minimal coupling

Autor: A. Emir Gümrükçüoğlu, Kazuya Koyama, Rampei Kimura

Publikováno v: Gumrukcuoglu, A E, Kimura, R & Koyama, K 2020, ' Massive gravity with nonminimal coupling ', Physical Review D, vol. 101, no. 12, 124021 . https://doi.org/10.1103/PhysRevD.101.124021
Gumrukcuoglu, E, Kimura, R & Koyama, K 2020, ' Massive gravity with non-minimal coupling ', Physical Review D-Particles, Fields, Gravitation and Cosmology, vol. 101, no. 12, 124021 . https://doi.org/10.1103/PhysRevD.101.124021
Physical Review D

We propose new massive gravity theories with 5 dynamical degrees of freedom. We evade uniqueness theorems regarding the form of the kinetic and potential terms by adopting the "generalized massive gravity" framework, where a global translation invari

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5648de3eb0336b50c01b6a7202e3ef5c
http://arxiv.org/abs/2003.11831

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Unified framework for early dark energy from α -attractors

Autor: Fabio Finelli, Matteo Braglia, A. Emir Gümrükçüoğlu, Kazuya Koyama, William T. Emond

Publikováno v: Physical Review D
Braglia, M, Emond, W T, Finelli, F, Gumrukcuoglu, A E & Koyama, K 2020, ' Unified framework for early dark energy from α-attractors ', Physical Review D-Particles, Fields, Gravitation and Cosmology, vol. 102, no. 8, 083513 . https://doi.org/10.1103/PhysRevD.102.083513

One of the most appealing approaches to ease the Hubble tension is the inclusion of an early dark energy (EDE) component that adds energy to the Universe in a narrow redshift window around the time of recombination and dilutes faster than radiation a

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Stable cosmology in generalized massive gravity

Autor: A. Emir Gümrükçüoğlu, Kazuya Koyama, Michael Kenna-Allison

Publikováno v: Physical Review D
Kenna-Allison, M, Gumrukcuoglu, A E & Koyama, K 2020, ' Stable cosmology in generalised massive gravity ', Physical Review D, vol. 101, no. 8, 084014 . https://doi.org/10.1103/PhysRevD.101.084014
Physical Review

We present a thorough analysis of the cosmological perturbations in Generalised Massive Gravity. This is an extension of de Rham-Gabadadze-Tolley theory where the translation invariance in the St\"uckelberg field space is broken. This allows the mass

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Role of matter in gravitation: Going beyond the Einstein-Maxwell theory

Autor: Ryo Namba, A. Emir Gümrükçüoğlu

Publikováno v: Physical Review D
Physical Review
Gumrukcuoglu, A E & Namba, R 2019, ' Role of matter in gravitation : going beyond the Einstein-Maxwell theory ', Physical Review D, vol. 100, no. 12, 124064 . https://doi.org/10.1103/PhysRevD.100.124064

For field theories in curved spacetime, defining how matter gravitates is part of the theory building process. In this letter, we adopt Bekenstein's multiple geometries approach to allow part of the matter sector to follow the geodesics on a general

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Generalising the matter coupling in massive gravity: a search for new interactions

Autor: A. Emir Gümrükçüoğlu, Kazuya Koyama

Publikováno v: Physical Review
Gumrukcuoglu, A E & Koyama, K 2019, ' Generalizing the matter coupling in massive gravity : a search for new interactions ', Physical Review D, vol. 99, no. 8, 084004 . https://doi.org/10.1103/PhysRevD.99.084004
Physical Review D

Massive gravity theory introduced by de Rham, Gabadadze, Tolley (dRGT) is restricted by several uniqueness theorems that protect the form of the potential and kinetic terms, as well as the matter coupling. These restrictions arise from the requiremen

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Hořava gravity after GW170817

Autor: A. Emir Gümrükçüoğlu, Thomas P. Sotiriou, Mehdi Saravani

Publikováno v: Gümrükçüoğlu, A E, Saravani, M & Sotiriou, T P 2018, ' Hořava gravity after GW170817 ', Physical Review D, vol. 97 . https://doi.org/10.1103/PhysRevD.97.024032
Physical Review D

The recent detection of gravitational wave GW170817 has placed a severe bound on the deviation of the speed of gravitational waves from the speed of light. We explore the consequences of this detection for Hořava gravity.

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c657b655f582b81a0e109476fdd15ec2
https://researchportal.port.ac.uk/ws/files/8893737/PhysRevD.97.024032.pdf

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