Results 1 to 10 of about 3,508 (162)

Topology induced first-order phase transitions in lattice quantum gravity

Journal of High Energy Physics, 2022
Causal Dynamical Triangulations (CDT) is a lattice formulation of quantum gravity, suitable for Monte-Carlo simulations which have been used to study the phase diagram of the model.
J. Ambjorn, J. Gizbert-Studnicki, A. Görlich, D. Németh   +3 more
doaj   +2 more sources

Planar diagrams, two-dimensional lattice gravity and surface models

Nuclear Physics B, 1985
Abstract Some discrete lattice models for quantum two-dimensional euclidean gravity are shown to be equivalent to zero-dimensional planar field theories. Explicit expressions are given for partition functions. A universal continuum limit exists for open surfaces, but not for closed ones, and is argued to describe a space with negative average ...
exaly   +2 more sources

Gravity in a lattice Boltzmann model [PDF]

Physical Review E, 2000
In this paper we consider the introduction of a body force, in the incompressible limit, into the lattice Boltzmann model. A number of methods are considered and their suitability to our objectives determined. When there is no density variation across the fluid, gravity can be introduced in the form of an altered pressure gradient.
Buick, James, Greated , C A
  +17 more sources

Diffusion-Localization Transition Point of Gravity Type Transport Model on Regular Ring Lattices and Bethe Lattices [PDF]

Journal of Statistical Physics, 2022
AbstractFocusing on the diffusion-localization transition, we theoretically analyzed a nonlinear gravity-type transport model defined on networks called regular ring lattices, which have an intermediate structure between the complete graph and the simple ring.
Hajime Koike, Hideki Takayasu, Misako Takayasu   +2 more
openaire   +2 more sources

Lorentzian quantum gravity via Pachner moves: one-loop evaluation

Journal of High Energy Physics, 2023
Lorentzian quantum gravity is believed to cure the pathologies encountered in Euclidean quantum gravity, such as the conformal factor problem. We show that this is the case for the Lorentzian Regge path integral expanded around a flat background.
Johanna N. Borissova, Bianca Dittrich
doaj   +1 more source

Emergent time, cosmological constant and boundary dimension at infinity in combinatorial quantum gravity

Journal of High Energy Physics, 2022
Combinatorial quantum gravity is governed by a discrete Einstein-Hilbert action formulated on an ensemble of random graphs. There is strong evidence for a second-order quantum phase transition separating a random phase at strong coupling from an ordered,
C. A. Trugenberger
doaj   +1 more source

Effective de Sitter space, quantum behaviour and large-scale spectral dimension (3+1)

Journal of High Energy Physics, 2023
De Sitter space-time, essentially our own universe, is plagued by problems at the quantum level. Here we propose that Lorentzian de Sitter space-time is not fundamental but constitutes only an effective description of a more fundamental quantum gravity ...
C. A. Trugenberger
doaj   +1 more source

Modelling gravity on a hyper-cubic lattice [PDF]

Physical Review D, 2012
We present an elegant and simple dynamical model of symmetric, non-degenerate (n x n) matrices of fixed signature defined on a n-dimensional hyper-cubic lattice with nearest-neighbor interactions. We show how this model is related to General Relativity, and discuss multiple ways in which it can be useful for studying gravity, both classical and quantum.
Tate, Kyle, Visser, Matt
openaire   +2 more sources

The phase structure and effective action of 3D CDT at higher spatial genus

Journal of High Energy Physics, 2022
We perform a detailed investigation of the phase structure and the semiclassical effective action of (2+1)-dimensional Causal Dynamical Triangulations (CDT) quantum gravity using computer simulations. On the one hand, we study the effect of enlarging the
Joren Brunekreef, Dániel Németh
doaj   +1 more source

Lattice Chern-Simons gravity via the Ponzano-Regge model [PDF]

Nuclear Physics B, 1999
We propose a lattice version of Chern-Simons gravity and show that the partition function coincides with Ponzano-Regge model and the action leads to the Chern-Simons gravity in the continuum limit. The action is explicitly constructed by lattice dreibein and spin connection and is shown to be invariant under lattice local Lorentz transformation and ...
Kawamoto, N., Nielsen, Holger Frits Bech, Sato, N.   +2 more
openaire   +3 more sources