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pro vyhledávání: '"Ambjorn, J."'
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. It has four phases characterized by different dominant geometries, d
Externí odkaz:
http://arxiv.org/abs/2202.07392
Autor:
Ambjorn, J., Watabiki, Y.
We show how a modified Friedmann equation, originating from a model of the universe built from a certain $W_3$ algebra, has the potential to explain the difference between the Hubble constants extracted from CMB data and from supernova data.
Com
Com
Externí odkaz:
http://arxiv.org/abs/2111.05087
Lattice formulations of gravity can be used to study non-perturbative aspects of quantum gravity. Causal Dynamical Triangulations (CDT) is a lattice model of gravity that has been used in this way. It has a built-in time foliation but is coordinate-i
Externí odkaz:
http://arxiv.org/abs/2103.15610
Using Monte-Carlo computer simulations, we study the impact of matter fields on the geometry of a typical quantum universe in the CDT model of lattice quantum gravity. The quantum universe has the size of a few Planck lengths and the spatial topology
Externí odkaz:
http://arxiv.org/abs/2103.00198
Using computer simulations we study the geometry of a typical quantum universe, i.e. the geometry one might expect before a possible period of inflation. We display it using coordinates defined by means of four classical scalar fields satisfying the
Externí odkaz:
http://arxiv.org/abs/2101.08617
Publikováno v:
Phys. Rev. D 103, 086022 (2021)
We investigate the geometry of a quantum universe with the topology of the four-torus. The study of non-contractible geodesic loops reveals that a typical quantum geometry consists of a small semi-classical toroidal bulk part, dressed with many outgr
Externí odkaz:
http://arxiv.org/abs/2007.13311
A hallmark of non-perturbative theories of quantum gravity is the absence of a fixed background geometry, and therefore the absence in a Planckian regime of any notion of length or scale that is defined a priori. This has potentially far-reaching con
Externí odkaz:
http://arxiv.org/abs/2002.01693
Publikováno v:
Class. Quantum Grav. 36, 224001 (2019)
Four-dimensional CDT (causal dynamical triangulations) is a lattice theory of geometries which one might use in an attempt to define quantum gravity non-perturbatively, following the standard procedures of lattice field theory. Being a theory of geom
Externí odkaz:
http://arxiv.org/abs/1904.05755
We study perturbations around the generalized Kazakov multicritical one-matrix model. The multicritical matrix model has a potential where the coefficients of $z^n$ only fall off as a power $1/n^{s+1}$. This implies that the potential and its derivat
Externí odkaz:
http://arxiv.org/abs/1712.03879
Autor:
Ambjorn, J., Watabiki, Y.
Publikováno v:
Mod. Phys. Lett. A, Vol. 32, No. 40 (2017) 1750224
We recently formulated a model of the universe based on an underlying W3-symmetry. It allows the creation of the universe from nothing and the creation of baby universes and wormholes for spacetimes of dimension 2, 3, 4, 6 and 10. Here we show that t
Externí odkaz:
http://arxiv.org/abs/1709.06497