Signature Change of the Metric in CDT Quantum Gravity?

Abstract

We study the effective transfer matrix within the semiclassical and bifurcation phases of CDT quantum gravity. We find that for sufficiently large lattice volumes the kinetic term of the effective transfer matrix has a different sign in each of the two phases. We argue that this sign change can be viewed as a Wick rotation of the metric. We discuss the likely microscopic mechanism responsible for the bifurcation phase transition, and propose an order parameter that can potentially be used to determine the precise location and order of the transition. Using the effective transfer matrix we approximately locate the position of the bifurcation transition in some region of coupling constant space, allowing us to present an updated version of the CDT phase diagram.

16 pages, 9 figures

References in corpus (5)

• Asymptotic safety in higher-derivative gravity
• Ultraviolet properties of f(R)-Gravity
• Quantum Gravity on the Lattice
• Anomaly-free cosmological perturbations in effective canonical quantum gravity
• The effective action in 4-dim CDT. The transfer matrix approach

Cited by in corpus (21)

• Quantum Gravity from Causal Dynamical Triangulations: A Review
• Characteristics of the new phase in CDT
• New higher-order transition in causal dynamical triangulations
• Impact of topology in causal dynamical triangulations quantum gravity
• The phase structure of Causal Dynamical Triangulations with toroidal spatial topology
• Towards the map of quantum gravity
• Signature change in matrix model solutions
• Exploring the new phase transition of CDT
• Spectrum of the Laplace-Beltrami Operator and the Phase Structure of Causal Dynamical Triangulation
• Towards an UV fixed point in CDT gravity
• CDT and Cosmology
• The higher-order phase transition in toroidal CDT
• Critical Phenomena in Causal Dynamical Triangulations
• Riemann-Cartan gravity with dynamical signature
• Probing the Planck scale: The modification of the time evolution operator due to the quantum structure of spacetime
• Euclidean Action and the Einstein tensor
• Fuzzy $C{P}^2$ Space-Times
• Spectral Methods and Running Scales in Causal Dynamical Triangulations
• The continuum limit of quantum gravity at second order in perturbation theory
• A second look at transition amplitudes in (2+1)-dimensional causal dynamical triangulations
• Singularity at the demise of a black hole