A new quantization principle from a minimally non time-ordered product

Abstract

We formulate a new quantization principle for perturbative quantum field theory, based on a minimally non time-ordered product, and show that it gives the theories of physical particles and purely virtual particles. Given a classical Lagrangian, the quantization proceeds as usual, guided by the time-ordered product, up to the common scattering matrix $S$, which satisfies a unitarity or a pseudounitarity equation. The physical scattering matrix $S_{\text{ph}}$ is built from $S$, by gluing $S$ diagrams together into new diagrams, through non time-ordered propagators. We classify the most general way to gain unitarity by means of such operations, and point out that a special solution "minimizes" the time-ordering violation. We show that the scattering matrix $S_{\text{ph}}$ given by this solution coincides with the one obtained by turning the would-be ghosts (and possibly some would-be physical particles) into purely virtual particles (fakeons). We study tricks to descend and ascend in a unique way among diagrams, and illustrate them in several examples: the ascending chain from the bubble to the hexagon, at one loop; the box with diagonal, at two loops; other diagrams, with more loops.

54 pages; 6 figures; v2: JHEP

References in corpus (3)

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Cited by in corpus (10)

• Ultraviolet-complete quantum field theories with fractional operators
• Visions in Quantum Gravity
• Quantum field theory of physical and purely virtual particles in a finite interval of time on a compact space manifold: diagrams, amplitudes and unitarity
• Lectures in Quantum Gravity
• Classicized dynamics and initial conditions in field theories with fakeons
• Purely virtual extension of quantum field theory for gauge invariant fields: quantum gravity
• Quantum gravity with purely virtual particles from asymptotically local quantum field theory
• Gauge theories and quantum gravity in a finite interval of time, on a compact space manifold
• Cosmological inhomogeneities, primordial black holes, and a hypothesis on the death of the universe
• Acausal exact vacuum solutions in nonlocal gravity