Speaker
Description
The Ising model at criticality is a paradigmatic example of random variables displaying strong correlations at all scales. In the high and low temperature phases, the collective properties of the system are described by the standard (Gaussian) central limit theorem. In contrast, at the critical point separating the two phases, the fluctuations are non-Gaussian and are captured by a scale-invariant and universal asymptotic probability distribution. From a physicist's point of view, the emergence of such a probability distribution is understood using the renormalization group, which effectively describes the behavior of coarse-grained random variables.
In this talk, I will discuss the extension of this problem to quantum systems, using the probability distribution of the order parameter as an example of a non-trivial observable displaying non-Gaussian fluctuations at criticality. The observation of such non-Gaussianity in a recent ultracold-atom experiment will also be discussed.
| Affiliation | Université de Lille |
|---|---|
| Career status | Senior |