Aspects of perturbative unitarity
arXiv:1606.06348 · doi:10.1103/PhysRevD.94.025028
Abstract
We reconsider perturbative unitarity in quantum field theory and upgrade several arguments and results. The minimum assumptions that lead to the largest time equation, the cutting equations and the unitarity equation are identified. Using this knowledge and a special gauge, we give a new, simpler proof of perturbative unitarity in gauge theories and generalize it to quantum gravity, in four and higher dimensions. The special gauge interpolates between the Feynman gauge and the Coulomb gauge without double poles. When the Coulomb limit is approached, the unphysical particles drop out of the cuts and the cutting equations are consistently projected onto the physical subspace. The proof does not extend to nonlocal quantum field theories of gauge fields and gravity, whose unitarity remains uncertain.
37 pages, 9 figures; v2: minor changes, Phys. Rev. D
References in corpus (14)
- Towards singularity and ghost free theories of gravity
- Super-renormalizable Quantum Gravity
- Super-renormalizable & Finite Gravitational Theories
- Generalized ghost-free quadratic curvature gravity
- Superrenormalizable gauge and gravitational theories
- Anomalies to All Orders
- Weighted scale invariant quantum field theories
- Physical Unitarity for Massive Non-abelian Gauge Theories in the Landau Gauge: Stueckelberg and Higgs
- Properties Of The Classical Action Of Quantum Gravity
- Weighted power counting and chiral dimensional regularization
- Finite Quantum Gravity
- Adler-Bardeen theorem and manifest anomaly cancellation to all orders in gauge theories
- Adler-Bardeen theorem and cancellation of gauge anomalies to all orders in nonrenormalizable theories
- Ward identities and gauge independence in general chiral gauge theories
Cited by in corpus (17)
- Ghost-free infinite derivative quantum field theory
- Fakeons And Lee-Wick Models
- On the quantum field theory of the gravitational interactions
- Perturbative unitarity of Lee-Wick quantum field theory
- The Ultraviolet Behavior Of Quantum Gravity
- Generalized ghost-free propagators in nonlocal field theories
- Nonlocal generalization of Galilean theories and gravity
- Unitarity and microscopic acausality in a nonlocal theory
- On the contour prescriptions in string-inspired nonlocal field theories
- Quantum field theories of arbitrary-spin massive multiplets and Palatini quantum gravity
- Fakeons, unitarity, massive gravitons and the cosmological constant
- S-matrix Unitarity and Renormalizability in Higher Derivative Theories
- Lectures in Quantum Gravity
- Purely virtual extension of quantum field theory for gauge invariant fields: Yang-Mills theory
- Purely virtual extension of quantum field theory for gauge invariant fields: quantum gravity
- Algebraic cutting equations
- Gauge theories and quantum gravity in a finite interval of time, on a compact space manifold