Speaker: Nicolas Boulle
What is a quantum system? It is not always obvious to define the notion of a system because it depends on what we take into account to be part of it. A quantum system is at least made of a state, a Hamiltonian with a given basis and a Hilbert space. The Hilbert space can be made of a lot of subspaces that one can « glue » together to get a total space for the whole system: this is the Hilbert space factorization. I am going to talk about how the Hilbert state can be factorized and why it is important to choose a good factorization depending on how you want your system to look like.
Speaker: David Stuhrmann
What happens when you sum random variables? If you are interested in a very unlikely outcome, the so-called rare event, it is important to know the shape of the resulting probability distribution. Large Deviation Theory is a good framework because it looks at probabilities in a logarithmic scale. I will motivate this idea with an example of repeated coin flips. In the end, I show the connection to statistical physics and explain how entropy appears from Large Deviation Theory.