Séminaire de Probabilités commun ICJ/UMPA

The critical and supercritical Liouville quantum gravity metrics

par Ewain Gwynne

Europe/Paris
BBB (UMPA)

BBB

UMPA

Description

Liouville first passage percolation (LFPP) with parameter $\xi  >0$ is the family of random distance functions on the plane obtained by integrating $e^{\xi h_\epsilon}$ along paths, where $h_\epsilon$ for $\epsilon >0$ is a smooth mollification of the planar Gaussian free field.
Previous work by Ding-Dub\'edat-Dunlap-Falconet and Gwynne-Miller showed that there is a critical value $\xi_{\mathrm{crit}} > 0$ such that for $\xi < \xi_{\mathrm{crit}}$, LFPP converges under appropriate re-scaling to a random metric on the plane which induces the same topology as the Euclidean metric: the so-called $\gamma$-Liouville quantum gravity metric for $\gamma  = \gamma(\xi)\in (0,2)$.

Recently, Jian Ding and I showed that LFPP also converges when $\xi \geq \xi_{\mathrm{crit}}$.
For $\xi  >\xi_{\mathrm{crit}}$, the subsequential limiting metrics do not induce the Euclidean topology. Rather, there is an uncountable, dense, Lebesgue measure-zero set of points $z\in\mathbb C $ such that $D_h(z,w) = \infty$ for every $w\in\mathbb C\setminus \{z\}$.
These metrics are related to a supercritical phase of Liouville quantum gravity, corresponding to matter central charge in $(1,25)$.  

I will discuss the properties of the limiting metrics, their connection to Liouville quantum gravity, and several open problems.