Talks

I explain what physicists mean when they say that space and time may be relational and discuss the extent to which different of the contemporary attempts at quantum gravity satisfy this criteria. I then discuss how the current debates between advocates of background dependent and background independent theories may be seen in the light of the historical debate in philosophy between advocates of absolute and relational notions of space and time.

Anton Zeilinger, a renowned physicist who successfully teleported light particles, will explain how quantum properties are used today to process and transmit information. Anton Zeilinger, Einstein, quantum information, quantum physics, entanglement, cryptography, quantum mechanics, teleportation, quantum computer

Understanding how galaxies form is a major current goal in physical cosmology: although a basic picture is well-accepted, there are outstanding mysteries to be solved. First, what is the origin of the heavy elements seen outside of galaxies? Given that these elements are created only inside galaxies, there must be a process whereby galaxies can expel gas rather than accrete it. Second, galaxy properties are somewhat different from theory predicts, yet extremely regular -- to the extent that it has been seriously argued that modified gravity, rather than dark matter, explains them. I will discuss these mysteries and the possibility that the same culprit -- galactic winds -- may play a key role in solving both.

It was conjectured that the N=4 Yang-Mills perturbation theory in the sector with large R charges corresponds to considering the classical string worldsheets in $AdS_5imes S^5$ as perturbations of the null-surfaces. We discuss this perturbation theory with a special emphasis on a hidden symmetry.