The standard model of cosmology is built upon the assumptions of homogeneity and isotropy. Invoking backreaction of inhomogeneities leads to an alternative model, the timescape cosmology. It is homogeneous and isotropic on a statistical level but departs from average Friedmann-Lemaître-Robertson-Walker evolution and replaces dark energy by kinetic gravitational energy and its gradients.
In this talk, I will give an overview of the timescape cosmology and present a statistical analysis of the Pantheon+ Type Ia Supernovae spectroscopic comparing the timescape and spatially flat ΛCDM cosmological models. This analysis is based on the Tripp equation for supernova standardisation alone, thereby avoiding any potential correlation in the stretch and colour distributions and finds very strong evidence (ln B > 5) in favour of timescape over ΛCDM when considering the entire Pantheon+ sample.
In the panel discussion, each panelist will showcase examples of well-written papers and share one essential "do" and one important "don't" for crafting effective scientific papers. The session will include an open Q&A segment to encourage audience engagement.
the no-cloning theorem is an essential result in quantum information on top of which many quantum cryptography protocols are built. In this talk we examine the cloning question in the context of classical mechanics/Hamiltonian mechanics. We find the answer is quite subtle: whether a mechanical system can be cloned depends on the topological structure of its phase space. In particular, for a system to be clonable, its phase space must be contractible. This means certain systems (e.g. particle moving on a line) is clonable, while others (e.g. the simple pendulum) cannot be cloned. We explain the idea of the proof, which uses tools from algebraic topology (homotopy groups and Whitehead’s theorem). Finally we discuss the physical interpretations of this result: how do we reconcile this theorem with the experience that generally speaking, classical information is clonable? Can we use this no-cloning theorem to build secure communication protocols in classical systems instead of quantum ones?