5 papers
Lie symmetries and ghost-free representations of the Pais-Uhlenbeck model
Alexander Felski, Andreas Fring, Bethan Turner
We investigate the Pais-Uhlenbeck (PU) model, a paradigmatic example of a higher time-derivative theory, by identifying the Lie symmetries of its associated fourth-order dynamical…
Bi-Hamiltonian Structures and Equivalent Representations of the Pais-Uhlenbeck Model
Bethan Turner
We provide a complete classification of all the ways the Pais-Uhlenbeck osicllator might be embedded in two dimensional space. We discuss the Bi-Hamiltonian structures of this mode…
Three-dimensional ghost-free representations of the Pais-Uhlenbeck model from Tri-Hamiltonians
Alexander Felski, Andreas Fring, Bethan Turner
We present a detailed analysis of the sixth-order Pais-Uhlenbeck oscillator and construct three-dimensional ghost-free representations through a Tri-Hamiltonian framework. We ident…
Ghost-Free Quantisation of Higher Time-Derivative Theories via Non-Unitary Similarity Transformations
Andreas Fring, Takano Taira, Bethan Turner
We address the long-standing ``ghost problem" in higher time-derivative theories (HTDTs), where quantisation typically yields sectors with either unbounded spectra or non-normalisa…
Quantisations of exactly solvable ghostly models
Andreas Fring, Takano Taira, Bethan Turner
We investigate an exactly solvable two-dimensional Lorentzian coupled quantum system that in a certain parameter regime can be transformed to a higher time derivative theory (HTDT)…