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We show how the large-scale cosmological dynamics can be obtained from the hydrodynamics of isotropic group field theory condensate states in the Gross-Pitaevskii approximation. The correct Friedmann equations are recovered in the…

General Relativity and Quantum Cosmology · Physics 2017-01-25 Daniele Oriti , Lorenzo Sindoni , Edward Wilson-Ewing

We identify a class of condensate states in the group field theory (GFT) approach to quantum gravity that can be interpreted as macroscopic homogeneous spatial geometries. We then extract the dynamics of such condensate states directly from…

General Relativity and Quantum Cosmology · Physics 2013-07-17 Steffen Gielen , Daniele Oriti , Lorenzo Sindoni

Recent results have shown how quantum cosmology models can be derived from the effective dynamics of condensate states in group field theory (GFT), where 'cosmology is the hydrodynamics of quantum gravity': the classical Friedmann dynamics…

General Relativity and Quantum Cosmology · Physics 2016-10-27 Steffen Gielen

Group field theory (GFT) models for quantum gravity coupled to a massless scalar field give rise to cosmological models that reproduce the (expanding or contracting) dynamics of homogeneous and isotropic spacetimes in general relativity at…

High Energy Physics - Theory · Physics 2023-07-27 Steffen Gielen , Robert Santacruz

We give a general procedure, in the group field theory (GFT) formalism for quantum gravity, for constructing states that describe macroscopic, spatially homogeneous universes. These states are close to coherent (condensate) states used in…

General Relativity and Quantum Cosmology · Physics 2014-06-06 Steffen Gielen , Daniele Oriti , Lorenzo Sindoni

We extend various recent results regarding the derivation of effective cosmological Friedmann equations from the dynamics of group field theory (GFT). Restricting ourselves to a single GFT field mode (or fixed values of Peter-Weyl…

General Relativity and Quantum Cosmology · Physics 2022-01-11 Steffen Gielen , Axel Polaczek

One of the fundamental challenges for quantum cosmology is to explain the emergence of our macroscopic Universe from physics at the Planck scale. In the group field theory (GFT) approach to quantum gravity, such a macroscopic universe…

General Relativity and Quantum Cosmology · Physics 2019-02-12 Steffen Gielen

We study the cosmological sector of the Lorentzian Barrett-Crane (BC) model coupled to a free massless scalar field in its Group Field Theory (GFT) formulation, corresponding to the mean-field hydrodynamics obtained from coherent condensate…

General Relativity and Quantum Cosmology · Physics 2022-01-31 Alexander F. Jercher , Daniele Oriti , Andreas G. A. Pithis

We derive an effective dynamics for scalar cosmological perturbations from quantum gravity, in the framework of group field theory (GFT) condensate cosmology. The emergent spacetime picture is obtained from the mean field hydrodynamic…

General Relativity and Quantum Cosmology · Physics 2022-07-19 Luca Marchetti , Daniele Oriti

In this review we focus on the main cosmological implications of the Group Field Theory approach, according to which an effective continuum macroscopic dynamics can be extracted from the underlying formalism for quantum gravity. Within this…

General Relativity and Quantum Cosmology · Physics 2022-04-27 Luciano Gabbanelli , Silvia De Bianchi

The condensate cosmology programme of group field theory has produced several interesting results. The key idea is in the suggestion that a macroscopic homogeneous spacetime can be approximated by a dynamical condensate phase of the…

General Relativity and Quantum Cosmology · Physics 2020-08-18 Mehdi Assanioussi , Isha Kotecha

We study the dynamics of perturbations representing deviations from perfect isotropy in the context of the emergent cosmology obtained from the group field theory formalism for quantum gravity. Working in the mean field approximation of the…

General Relativity and Quantum Cosmology · Physics 2017-12-12 Marco de Cesare , Daniele Oriti , Andreas G. A. Pithis , Mairi Sakellariadou

In this work we present a derivation of modified Raychaudhuri and Friedmann equations from a phenomenological model of quantum gravity based on the thermodynamics of spacetime. Starting from general gravitational equations of motion which…

General Relativity and Quantum Cosmology · Physics 2023-09-13 Ana Alonso-Serrano , Marek Liška , Antonio Vicente-Becerril

We study the impact of effective interactions onto relationally evolving GFT condensates based on real-valued fields. In a first step we show that a free condensate configuration in an isotropic restriction settles dynamically into a…

General Relativity and Quantum Cosmology · Physics 2017-03-08 Andreas G. A. Pithis , M. Sakellariadou

In a recent proposal using the group field theory approach, a spatially homogeneous (generally anisotropic) universe is described as a quantum gravity condensate of "atoms of space," which allows the derivation of an effective cosmological…

General Relativity and Quantum Cosmology · Physics 2015-02-23 Steffen Gielen

This is an introduction to the approach to the extraction of cosmological dynamics from full quantum gravity based on group field theory condensates. We outline its general perspective, which sees cosmology as the hydrodynamics of the…

General Relativity and Quantum Cosmology · Physics 2017-04-25 Daniele Oriti

We present a systematic study of the cosmological dynamics resulting from an effective Hamiltonian, recently derived in loop quantum gravity using Thiemann's regularization and earlier obtained in loop quantum cosmology (LQC) by keeping the…

General Relativity and Quantum Cosmology · Physics 2018-04-25 Bao-Fei Li , Parampreet Singh , Anzhong Wang

A central open problem in quantum gravity is to understand how continuum spacetime emerges from quantum-geometric degrees of freedom in a background-independent setting. A many-body perspective suggests that spacetime emerges as a…

General Relativity and Quantum Cosmology · Physics 2026-05-20 Andrea Calcinari , Adrià Delhom , Daniele Oriti

A key result of isotropic loop quantum cosmology is the existence of a quantum bounce which occurs when the energy density of the matter field approaches a universal maximum close to the Planck density. Though the bounce has been exhibited…

General Relativity and Quantum Cosmology · Physics 2015-06-18 Peter Diener , Brajesh Gupt , Parampreet Singh

We study the emergent dynamics of an anisotropic universe in the context of Group Field Theory condensate cosmology, with a scalar field playing the role of a relational clock. According to different definitions of ``isotropy'', two…

General Relativity and Quantum Cosmology · Physics 2024-07-24 Daniele Oriti , Yi-Li Wang
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