English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The spinfoam framework defines transition amplitudes for spin network states of loop quantum gravity. I will review their recent reformulation in terms of spinorial variables allowing to see these amplitudes as coherent state path integrals [1,2,3]. This clarifies their geometrical meaning and at the identification of symmetries: recursion relations for 3nj symbols are turned into Hamiltonian constraints satisfied by the spinfoam amplitudes [4,5]. This applies in particular to the derivation of modified FRW equations for quantum cosmology [6]. References [1] L Freidel and S Speziale, From twistors to twisted geometries, Phys. Rev. D 82, 084041 (2010) arXiv:1006.0199 [gr-qc] [2] E F Borja, L Freidel, I Garay and E R Livine, U(N) tools for Loop Quantum Gravity: The Return of the Spinor, Class. Quant. Grav. 28, 055005 (2011) arXiv:1010.5451 [gr-qc] [3] M Dupuis and E R Livine, Holomorphic Simplicity Constraints for 4d Riemannian Spinfoam Models, J. Phys. Conf. Ser. 360, 012046 (2012) arXiv:1111.1125 [gr-qc] [4] V Bonzom, E R Livine and S Speziale, Recurrence relations for spin foam vertices, Class. Quant. Grav. 27, 125002 (2010) arXiv:0911.2204 [gr-qc] [5] V Bonzom and E R Livine, Generating Functions for Coherent Intertwiners, Class. Quant. Grav. 30, 055018 (2013) arXiv:1205.5677 [gr-qc] [6] E R Livine and M Martin-Benito, Classical Setting and Effective Dynamics for Spinfoam Cosmology, Class. Quant. Grav. 30, 035006 (2013) arXiv:1111.2867 [gr-qc]

Spinorial Path Integral for Loop Gravity: Coherent states and Spinfoam symmetries