26 citations · 85 across the 10 of their papers we have counts for
10 papers
(2+1) Lorentzian quantum cosmology from spin-foams: opportunities and obstacles for semi-classicality
Alexander F. Jercher, José Diogo Simão, Sebastian Steinhaus
We construct an effective cosmological spin-foam model for a (2+1) dimensional spatially flat universe, discretized on a hypercubical lattice, containing both space- and time-like…
Phase transitions in TGFT: Landau-Ginzburg analysis of the causally complete Lorentzian Barrett-Crane model
Roukaya Dekhil, Alexander F. Jercher, Andreas G. A. Pithis
It is expected that continuum spacetime emerges via phase transition in the tensorial group field theory (TGFT) approach to quantum gravity. Recent work on the application of Landa…
Partial absence of cosine problem in 3d Lorentzian spin foams
Alexander F. Jercher, José Diogo Simão, Sebastian Steinhaus
We study the semi-classical limit of the recently proposed coherent spin foam model for (2+1) Lorentzian quantum gravity. Specifically, we analyze the gluing equations derived from…
Scale invariance beyond criticality within the mean-field analysis of tensorial field theories
Roukaya Dekhil, Alexander F. Jercher, Daniele Oriti +1
We continue the series of articles on the application of Landau-Ginzburg mean-field theory to unveil the basic phase structure of tensorial field theories which are characterized b…
Cosmology in Lorentzian Regge calculus: causality violations, massless scalar field and discrete dynamics
Alexander F. Jercher, Sebastian Steinhaus
We develop a model of spatially flat, homogeneous and isotropic cosmology in Lorentzian Regge calculus, employing 4-dimensional Lorentzian frusta as building blocks. By examining t…
Scalar Cosmological Perturbations from Quantum Gravitational Entanglement
Alexander F. Jercher, Luca Marchetti, Andreas G. A. Pithis
A major challenge at the interface of quantum gravity and cosmology is to explain the emergence of the large-scale structure of the Universe from Planck scale physics. In this lett…
Scalar Cosmological Perturbations from Quantum Entanglement within Lorentzian Quantum Gravity
Alexander F. Jercher, Luca Marchetti, Andreas G. A. Pithis
We derive the dynamics of (isotropic) scalar perturbations from the mean-field hydrodynamics of full Lorentzian quantum gravity, as described by a two-sector (timelike and spacelik…
Curvature effects in the spectral dimension of spin foams
Alexander Jercher, Sebastian Steinhaus, Johannes Thürigen
It has been shown in [1] that a class of restricted spin foam models can feature a reduced spectral dimension of space-time. However, it is still an open question how curvature aff…
The Complete Barrett-Crane Model and its Causal Structure
Alexander F. Jercher, Daniele Oriti, Andreas G. A. Pithis
The causal structure is a quintessential element of continuum spacetime physics and needs to be properly encoded in a theory of Lorentzian quantum gravity. Established spin foam (a…
Emergent Cosmology from Quantum Gravity in the Lorentzian Barrett-Crane Tensorial Group Field Theory Model
Alexander F. Jercher, Daniele Oriti, Andreas G. A. Pithis
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 th…