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arXiv · 2307.11741

Exorcizing Ghosts from the Vacuum Spectra in String-inspired Nonlocal Tachyon Condensation

Florian Nortier
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Abstract

Tachyon condensation in quantum field theory (QFT) plays a central role in models of fundamental interactions and cosmology. Inspired by tower truncation in string field theory, ultraviolet completions were proposed with infinite-derivative form factors that preclude the appearance of pathological ghosts in the particle spectrum, contrary to other local higher-derivative QFT's. However, if the infinite-derivative QFT exhibits other vacua, each of them has its own spectrum, which is generally not ghost-free: an infinite tower of ghost-like resonances pops up above the nonlocal scale at tree-level, whose consistency is unclear. In this article, a new weakly nonlocal deformation of a generic local QFT is introduced via a Lorentz and gauge covariant star-product of fields, which is commutative but nonassociative in general. This framework realizes tachyon condensation without ghosts at the perturbative level, with applications for spontaneous symmetry breaking.

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Florian Nortier. 2023-07-21. Exorcizing Ghosts from the Vacuum Spectra in String-inspired Nonlocal Tachyon Condensation. https://doi.org/10.5506/aphyspolb.54.9-a4

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