Webinar:- Ghosts without Runaway
The speaker will discuss his team’s recent work Phys.Rev.Lett. 128 (2022) 4, 041301 in which they present a simple class of mechanical models where a canonical degree freedom interacts with another one with a negative kinetic term, i.e., with a ghost. They prove analytically that the classical motion of the system is completely stable for all initial conditions, notwithstanding that the conserved Hamiltonian is unbounded from below and above. Numerical computations fully supported this. Systems with negative kinetic terms often appear in modern cosmology, quantum gravity, and high energy physics and are usually deemed as unstable. Their result demonstrates that for mechanical systems this common lore can be too naïve and that living with ghosts can be stable.
講者： Alexander Vikman(CEICO, Institute of Physics of the Czech Academy of Sciences)
“Copernicus Webinar and Colloquium Series”: To promote scientific discussions during this pandemic, they are organizing an online seminar series, i.e. Copernicus Webinar Series, seeking the most outstanding speakers to introduce innovative ideas and important progress in the field of gravity and cosmology. This series is named after the famous Polish Astronomer, Nicolaus Copernicus, whose discovery eventually marked the dawn of modern science.