3 papers
hep-th2026
Quantum mechanics with a ghost: Counterexamples to spectral denseness
Cédric Deffayet, Atabak Fathe Jalali, Aaron Held +2
We quantise integrable point-particle systems with opposite-sign kinetic terms and nontrivial interactions. Using methods from separability theory, we show that previously determin…
hep-th2026
Unitary Time Evolution and Vacuum for a Quantum Stable Ghost
Cédric Deffayet, Atabak Fathe Jalali, Aaron Held +2
We quantize a classically stable system of a harmonic oscillator polynomially coupled to a ghost with negative kinetic energy. We prove that due to an integral of motion with a pos…
hep-th2025
Ghostly interactions in (1+1) dimensional classical field theory
Cédric Deffayet, Aaron Held, Shinji Mukohyama +1
We investigate the classical stability of two coupled scalar fields with opposite-sign kinetic terms evolving in 1+1 dimensional Minkowski spacetime. In the first part, we characte…