Causal Dynamical Triangulations: New Lattice Theory of Quantum Gravity
Fuente:
arXiv
Saved in:
| Main Authors: | , |
|---|---|
| Format: | Preprint |
| Published: |
2026
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866910107678277632 |
|---|---|
| author | Ambjørn, J. Loll, R. |
| author_facet | Ambjørn, J. Loll, R. |
| contents | Causal Dynamical Triangulations (CDT) is a methodology to define and compute the gravitational path integral, whose aim is a fully fledged nonperturbative quantum field theory of gravity and spacetime. Analogous to lattice formulations of nongravitational quantum fields, CDT provides a blueprint for lattice quantum gravity, where - crucially - the dynamical, curved and causal nature of spacetime is built into the structure of the lattices from the outset. The regularized path integral involves a sum over triangulated spacetimes, each assembled from flat, Minkowskian building blocks. The degrees of freedom of general relativity are encoded in a coordinate-free manner in the neighbourhood relations of the building blocks and the length of their edges, which also serves as a short-distance cutoff.
A well-defined Wick rotation makes this path integral amenable to Monte Carlo simulations. Despite the absence of an a priori preferred background geometry, numerical experiments have revealed the dynamical emergence of a quantum universe near the Planck scale. Its global properties are compatible with those of a de Sitter space, providing strong evidence for a well-defined classical limit. At the same time, large quantum fluctuations lead to unexpected properties on short scales, most prominently, a spectral dimension near 2, replacing the classical value of 4. Computer simulations indicate the presence of an ultraviolet fixed point under renormalization, opening the door to a nontrivial continuum theory. Efforts are under way to construct observables that can elucidate the nonperturbative quantum origins of early-universe cosmology. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_05641 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Causal Dynamical Triangulations: New Lattice Theory of Quantum Gravity Ambjørn, J. Loll, R. High Energy Physics - Theory General Relativity and Quantum Cosmology High Energy Physics - Lattice Causal Dynamical Triangulations (CDT) is a methodology to define and compute the gravitational path integral, whose aim is a fully fledged nonperturbative quantum field theory of gravity and spacetime. Analogous to lattice formulations of nongravitational quantum fields, CDT provides a blueprint for lattice quantum gravity, where - crucially - the dynamical, curved and causal nature of spacetime is built into the structure of the lattices from the outset. The regularized path integral involves a sum over triangulated spacetimes, each assembled from flat, Minkowskian building blocks. The degrees of freedom of general relativity are encoded in a coordinate-free manner in the neighbourhood relations of the building blocks and the length of their edges, which also serves as a short-distance cutoff. A well-defined Wick rotation makes this path integral amenable to Monte Carlo simulations. Despite the absence of an a priori preferred background geometry, numerical experiments have revealed the dynamical emergence of a quantum universe near the Planck scale. Its global properties are compatible with those of a de Sitter space, providing strong evidence for a well-defined classical limit. At the same time, large quantum fluctuations lead to unexpected properties on short scales, most prominently, a spectral dimension near 2, replacing the classical value of 4. Computer simulations indicate the presence of an ultraviolet fixed point under renormalization, opening the door to a nontrivial continuum theory. Efforts are under way to construct observables that can elucidate the nonperturbative quantum origins of early-universe cosmology. |
| title | Causal Dynamical Triangulations: New Lattice Theory of Quantum Gravity |
| topic | High Energy Physics - Theory General Relativity and Quantum Cosmology High Energy Physics - Lattice |
| url | https://arxiv.org/abs/2604.05641 |