A spin-foam vertex amplitude with the correct semiclassical limit

Abstract

Spin-foam models are hoped to provide a dynamics for loop quantum gravity. These start from the Plebanski formulation of gravity, in which gravity is obtained from a topological field theory, BF theory, through constraints, which, however, select more than one gravitational sector, as well as an unphysical degenerate sector. We show this is why terms beyond the needed Feynman-prescribed one appear in the semiclassical limit of the EPRL spin-foam amplitude. By quantum mechanically isolating a single gravitational sector, we modify this amplitude, yielding a spin-foam amplitude for loop quantum gravity with the correct semiclassical limit.

5 pages; sign error corrected, further clarification regarding the semi-classical limit added, as well as other minor changes

References in corpus (9)

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Cited by in corpus (27)

• The Spin Foam Approach to Quantum Gravity
• SL(2,C) Chern-Simons Theory, a non-Planar Graph Operator, and 4D Loop Quantum Gravity with a Cosmological Constant: Semiclassical Geometry
• Effective Spin Foam Models for Four-Dimensional Quantum Gravity
• Effective Spin Foam Models for Lorentzian Quantum Gravity
• Imaginary action, spinfoam asymptotics and the 'transplanckian' regime of loop quantum gravity
• A proposed proper EPRL vertex amplitude
• Discrete gravity dynamics from effective spin foams
• Linking covariant and canonical LQG II: Spin foam projector
• Lorentzian quantum cosmology goes simplicial
• Emergent 4-dimensional linearized gravity from spin foam model
• The Lorentzian proper vertex amplitude: Asymptotics
• The Lorentzian proper vertex amplitude: Classical analysis and quantum derivation
• The Construction of Spin Foam Vertex Amplitudes
• Diffeomorphism invariant cosmological sector in loop quantum gravity
• Lorentzian quantum cosmology from effective spin foams
• One vertex spin-foams with the Dipole Cosmology boundary
• Spinfoams: Foundations
• Coupled intertwiner dynamics: A toy model for coupling matter to spin foam models
• Cosine problem in EPRL/FK spinfoam model
• Semi-Classical Holomorphic Transition Amplitudes in Covariant Loop Quantum Gravity
• Spinfoam cosmology with the proper vertex amplitude
• Spin foams
• Causal structure in spin-foams
• A note on the spinor construction of Spin Foam amplitudes
• Hessian and graviton propagator of the proper vertex
• Purely geometric path integral for spin foams
• Coherent states for fractional powers of the harmonic oscillator Hamiltonian