Tachyon Dynamics in Quantum Field Theories

The concept of tachyons—particles possessing imaginary rest mass and superluminal propagation—has long challenged the foundations of relativistic physics. Within quantum field theory, tachyonic modes first appear as instabilities signalling transitions between distinct vacuum states rather than manifest particles. Classical treatments introduce negative squared‐mass terms in the Lagrangian that drive spontaneous symmetry breaking and vacuum decay, as seen in early studies of scalar fields and string‐theory tachyon condensation. More recently, the formalism has been extended to spinor fields, prompting manifestly covariant quantisation schemes for space‐like dispersion relations that preserve gauge and chiral symmetries. These developments underscore the need to reconcile causality constraints with Lorentz invariance, leading to robust field‐theoretic frameworks in which helicity and energy‐momentum observables are reinterpreted. On the phenomenological front, searches for tachyonic signatures in cosmic neutrino data and hadronic cosmic‐ray events probe the possible existence of superluminal neutrino mass states. Together, theoretical and experimental advances continue to refine our understanding of tachyon dynamics and their broader implications for fundamental physics and cosmology.

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Tachyon Dynamics in Quantum Field Theories publication trend

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Technical terms

Tachyon: A hypothetical particle characterised by an imaginary rest mass, implying superluminal velocity.

Dispersion relation: The functional relationship between a particle’s energy and momentum that defines its propagation.

Field quantisation: The procedure of promoting classical fields to operators acting on a quantum Fock space.

Helicity: The component of a particle’s spin along its direction of motion.

Chirality: A property of fermions distinguishing left‐handed and right‐handed components under Lorentz transformations.

References

1. A Review of Searches for Evidence of Tachyons. Symmetry (2022).
2. Tachyonic Neutrinos: From the Cosmic Rays to Extragalactic Supernovae. Symmetry (2023).
3. Quantum field theory of space-like neutrino. European Physical Journal C (2021).
4. A Consistent Theory of Tachyons with Interesting Physics for Neutrinos †. Symmetry (2022).