2008/07/09 by Aldo Dector, Aldo Déctor, Hugo A. Morales-Técotl +6
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #Mechanical and Optical Resonators #Quantum Mechanics and Non-Hermitian Physics #Quantum Physics (quant-ph) #gr-qc #hep-th #quant-ph
paper · pdf · doi:10.48550/arxiv.0807.1520
5 pages
arxiv created 2008/07/09 · openalex publication_date 2008/07/09 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
A \em complex canonical transformation is found that takes the fourth order derivative Pais-Uhlenbeck oscillator into two independent harmonic oscillators thus showing that this model has energy bounded from below, unitary time-evolution and no negative norm states, or ghosts. Such transformation yields a positive definite inner product consistent with reality conditions in the Hilbert space. The method is illustrated by eliminating the negative norm states in a complex oscillator. Extensions to other higher order mechanical models and field theory are discussed.