Kristina Giesel (Universität Erlangen-Nürnberg), Benjamin Bahr (Universität Hamburg)
Spin networks and spin foam models (Benjamin Bahr)
While spin networks describe quantum versions of 3-geometries, spin foam models are proposals for transition amplitudes between spin networks, prescribing a tentative quantum dynamics. In my talk, I will briefly describe a geometric interpretation of spin networks in terms of coherent polyhedra, after which I will talk about a specific spin foam model and its connection to (discrete) general relativity.
Loop Quantum Gravity: From Classical to Quantum Gravity (Kristina Giesel)
Loop quantum gravity is a candidate for a theory of quantum gravity, which takes general relativity as its classical starting point. The quantum theory is obtained by applying canonical quantization to general relativity. For this purpose, the techniques known from quantum field theory need to be generalized. As a consequence, loop quantum gravity is based on a quantum field theory, which is in many aspects different from the quantum field theory, that is used to formulate the Standard Model of particle physics. The dynamics of the quantum theory is described by the so called quantum Einstein equations, the quantum analog of Einstein's equations. After a brief introduction to the framework of loop quantum gravity, we will discuss the current status of the dynamics and present further research directions currently addressed in loop quantum gravity.