Characteristics of the new phase in CDT.
The approach of Causal Dynamical Triangulations (CDT), a candidate theory of nonperturbative quantum gravity in 4D, turns out to have a rich phase structure. We investigate the recently discovered bifurcation phase [Formula: see text] and relate some of its characteristics to the presence of singular vertices of very high order. The transition lines separating this phase from the "time-collapsed"B-phase and the de Sitter phase [Formula: see text] are of great interest when searching for physical scaling limits. The work presented here sheds light on the mechanisms behind these transitions. First, we study how theB-[Formula: see text] transition signal depends on the volume fixing implemented in the simulations, and find results compatible with the previously determined second-order character of the transition. The transition persists in a transfer matrix formulation, where the system's time extension is taken to be minimal. Second, we relate the new [Formula: see text]-[Formula: see text] transition to the appearance of singular vertices, which leads to a direct physical interpretation in terms of a breaking of the homogeneity and isotropy observed in the de Sitter phase when crossing from [Formula: see text] to the bifurcation phase [Formula: see text].
The Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, 2100 Copenhagen Ø, Denmark.|Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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Ambjørn
Institute of Physics, Jagiellonian University, ul. prof. Stanislawa Lojasiewicza 11, 30-348 Kraków, Poland.
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Gizbert-Studnicki
The Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, 2100 Copenhagen Ø, Denmark.|Institute of Physics, Jagiellonian University, ul. prof. Stanislawa Lojasiewicza 11, 30-348 Kraków, Poland.
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Görlich
Institute of Physics, Jagiellonian University, ul. prof. Stanislawa Lojasiewicza 11, 30-348 Kraków, Poland.
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Jurkiewicz
Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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Klitgaard
Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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Loll