Discrete Symmetries in Covariant LQG
arXiv:1205.0733 · doi:10.1103/PhysRevD.86.064002
Abstract
We study time-reversal and parity ---on the physical manifold and in internal space--- in covariant loop gravity. We consider a minor modification of the Holst action which makes it transform coherently under such transformations. The classical theory is not affected but the quantum theory is slightly different. In particular, the simplicity constraints are slightly modified and this restricts orientation flips in a spinfoam to occur only across degenerate regions, thus reducing the sources of potential divergences.
8 pages, v2: Minor changes
References in corpus (9)
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- A new spinfoam vertex for quantum gravity
- A New Spin Foam Model for 4d Gravity
- The loop-quantum-gravity vertex-amplitude
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- Towards Spinfoam Cosmology
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Cited by in corpus (22)
- The Spin Foam Approach to Quantum Gravity
- The twistorial structure of loop-gravity transition amplitudes
- Imaginary action, spinfoam asymptotics and the 'transplanckian' regime of loop quantum gravity
- Discrete Gravity Models and Loop Quantum Gravity: a Short Review
- A relational Hamiltonian for group field theory
- Divergences and Orientation in Spinfoams
- The Complete Barrett-Crane Model and its Causal Structure
- Dimensional crossover of effective orbital dynamics in polar distorted 3He-A: Transitions to anti-spacetime
- The Construction of Spin Foam Vertex Amplitudes
- Holonomy-flux spinfoam amplitude
- Radiative corrections to the Lorentzian EPRL spin foam propagator
- Coupled intertwiner dynamics: A toy model for coupling matter to spin foam models
- Scalar Cosmological Perturbations from Quantum Entanglement within Lorentzian Quantum Gravity
- Cosine problem in EPRL/FK spinfoam model
- Negative temperature for negative lapse function
- Comment to the CPT-symmetric Universe: Two possible extensions
- Negative temperature: further extensions
- Semi-Classical Holomorphic Transition Amplitudes in Covariant Loop Quantum Gravity
- Two roads to antispacetime in polar distorted B phase: Kibble wall and half-quantum vortex
- Causal structure in spin-foams
- A note on the spinor construction of Spin Foam amplitudes
- A look at area Regge calculus