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Characteristics of the new phase in CDT
J Ambjørn1,2, J Gizbert-Studnicki3, A Görlich1,3
1The Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, 2100 Copenhagen Ø, Denmark.
Causal Dynamical Triangulations reveal a complex phase structure in quantum gravity. A newly found bifurcation phase is linked to singular vertices, impacting homogeneity and isotropy in the de Sitter phase.
Area of Science:
- Theoretical Physics
- Quantum Gravity
- Cosmology
Background:
- Causal Dynamical Triangulations (CDT) is a leading candidate for nonperturbative quantum gravity in 4-dimensions.
- CDT exhibits a complex phase structure, crucial for understanding the universe's fundamental properties.
- The recently discovered bifurcation phase ([Formula: see text]) and its transitions are key to finding physical scaling limits.
Purpose of the Study:
- To investigate the characteristics of the bifurcation phase ([Formula: see text]) in Causal Dynamical Triangulations.
- To elucidate the mechanisms behind the transitions between the bifurcation phase, the B-phase, and the de Sitter phase ([Formula: see text]).
- To explore the role of singular vertices in these phase transitions.
Main Methods:
- Analysis of the bifurcation phase ([Formula: see text]) and its relation to high-order singular vertices.
- Study of the B-[Formula: see text] transition, examining its dependence on volume fixing in simulations.
- Utilizing a transfer matrix formulation to analyze the B-[Formula: see text] transition with minimal time extension.
- Relating the [Formula: see text]-[Formula: see text] transition to the emergence of singular vertices.
Main Results:
- The B-[Formula: see text] transition shows characteristics consistent with a second-order phase transition, independent of volume fixing methods.
- The transition remains robust in a transfer matrix formulation, confirming its fundamental nature.
- The [Formula: see text]-[Formula: see text] transition is directly linked to the appearance of singular vertices.
- Singular vertices provide a physical interpretation for the breaking of homogeneity and isotropy when moving from the de Sitter phase to the bifurcation phase.
Conclusions:
- The bifurcation phase ([Formula: see text]) in Causal Dynamical Triangulations is characterized by singular vertices.
- These singular vertices are responsible for the breaking of homogeneity and isotropy observed at the [Formula: see text]-[Formula: see text] transition.
- Understanding these phase transitions is vital for identifying physical scaling limits in quantum gravity theories.
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