1.1k citations · 11.6k across the 67 of their papers we have counts for
65 papers
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…
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…
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…
Global and Local Stability for Ghosts Coupled to Positive Energy Degrees of Freedom
Cédric Deffayet, Aaron Held, Shinji Mukohyama +1
Negative kinetic energies correspond to ghost degrees of freedom, which are potentially of relevance for cosmology, quantum gravity, and high energy physics. We present a novel wid…
Ghosts without runaway
Cédric Deffayet, Shinji Mukohyama, Alexander Vikman
We present a simple class of mechanical models where a canonical degree of freedom interacts with another one with a negative kinetic term, i.e. with a ghost. We prove analytically…
Domain walls without a potential
Cédric Deffayet, François Larrouturou
We show that domain walls, or kinks, can be constructed in simple scalar theories where the scalar has no potential. These theories belong to a class of k-essence where the Lagrang…