14 citations · 24 across the 7 of their papers we have counts for
4 papers · 1 filter
Spectrum-generating algebra and intertwiners of the resonant Pais-Uhlenbeck oscillator
Andreas Fring, Ian Marquette, Takano Taira
We study the quantum Pais-Uhlenbeck oscillator at the resonant (equal-frequency) point, where the dynamics becomes non-diagonalisable and the conventional Fock-space construction c…
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…
Exact treatment of the memory kernel under time-dependent system-environment coupling via a train of delta distributions
Yuta Uenaga, Kensuke Gallock-Yoshimura, Takano Taira
Memory effects in a quantum system coupled to an environment are one of the central features in the theory of open quantum systems. The dynamics of such quantum systems are typical…
Real energies and Berry phases in all PT-regimes in time-dependent non-Hermitian theories
Andreas Fring, Takanobu Taira, Rebecca Tenney
We demonstrate that the existence of a Hermitian time-dependent intertwining operator that maps the non-Hermitian time-dependent energy operator to its Hermitian conjugate and its…