collaborators

5 papers

hep-th2026

Non-uniqueness of boundary-value problems in Renormalization Group flows

Astrid Eichhorn, Zois Gyftopoulos, Aaron Held

The Renormalization Group flow connects microscopic to macroscopic descriptions of a system and is therefore typically considered as an initial-value problem. Motivated by situatio…

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-ph2025

Quark and lepton mixing in the asymptotically safe Standard Model

Astrid Eichhorn, Zois Gyftopoulos, Aaron Held

The quark mixing (CKM) matrix is near-diagonal, whereas the lepton mixing (PMNS) matrix is not. We learn that both observations can generically be explained within an ultraviolet c…

hep-th2025

On the Renormalization Group flow of distributions

Astrid Eichhorn, Aaron Held

Renormalization Group flows relate the values of couplings at different scales. Here, we go beyond the Renormalization Group flow of individual trajectories and derive an evolution…