Causal structure in spin-foams
arXiv:2109.00986 · doi:10.3390/universe10040181
Abstract
The metric field of general relativity is almost fully determined by its causal structure. Yet, in spin-foam models for quantum gravity, the role played by the causal structure is still largely unexplored. The goal of this paper is to clarify how causality is encoded in such models. The quest unveils the physical meaning of the orientation of the two-complex and its role as a dynamical variable. We propose a causal version of the EPRL spin-foam model and discuss the role of the causal structure in the reconstruction of a semiclassical spacetime geometry.
28 pages
References in corpus (34)
- The Spin Foam Approach to Quantum Gravity
- LQG vertex with finite Immirzi parameter
- A Short Review of Loop Quantum Gravity
- Ponzano-Regge model revisited III: Feynman diagrams and Effective field theory
- Twisted geometries: A geometric parametrisation of SU(2) phase space
- Lorentzian spin foam amplitudes: graphical calculus and asymptotics
- Asymptotic analysis of the EPRL four-simplex amplitude
- The causal set approach to quantum gravity
- General boundary quantum field theory: Foundations and probability interpretation
- Casting Loop Quantum Cosmology in the Spin Foam Paradigm
- Zakopane lectures on loop gravity
- Lorentzian spinfoam propagator
- Implementing causality in the spin foam quantum geometry
- Evolution in Quantum Causal Histories
- A proposed proper EPRL vertex amplitude
- Asymptotics of lowest unitary SL(2,C) invariants on graphs
- A spin-foam vertex amplitude with the correct semiclassical limit
- The Feynman propagator for spin foam quantum gravity
- Local spinfoam expansion in loop quantum cosmology
- Discrete Symmetries in Covariant LQG
- A Primer of Group Theory for Loop Quantum Gravity and Spin-foams
- Divergences and Orientation in Spinfoams
- Causality and matter propagation in 3d spin foam quantum gravity
- Quantum causal histories in the light of quantum information
- Semiclassical regime of Regge calculus and spin foams
- The Complete Barrett-Crane Model and its Causal Structure
- Generalised group field theories and quantum gravity transition amplitudes
- New action for simplicial gravity in four dimensions
- Spin foam models as energetic causal sets
- The Lorentzian proper vertex amplitude: Classical analysis and quantum derivation
- The Construction of Spin Foam Vertex Amplitudes
- On the causal Barrett--Crane model: measure, coupling constant, Wick rotation, symmetries and observables
- Cosine problem in EPRL/FK spinfoam model
- A note on the spinor construction of Spin Foam amplitudes