## Electronic Journal of Probability

### On the heat kernel and the Dirichlet form of Liouville Brownian motion

#### Abstract

In a previous work, a Feller process called Liouville Brownian motion on $\mathbb{R}^2$ has been introduced. It can be seen as a Brownian motion evolving in a random geometry given formally by the exponential of a (massive) Gaussian Free Field $e^{\gamma\, X}$ and is the right diffusion process to consider regarding $2d$-Liouville quantum gravity.  In this note, we discuss the construction of the associated  Dirichlet form, following essentially Fukushima, Oshima, and Takeda, and the techniques introduced in our previous work. Then we carry  out the analysis of the Liouville resolvent. In particular, we prove that it is strong Feller, thus obtaining the existence of  the Liouville heat kernel via a non-trivial theorem of Fukushima and al. One of the motivations which led to introduce the Liouville Brownian motion in our previous work was to investigate the puzzling Liouville metric through the eyes of this new stochastic process. In particular,  the theory developed for example in Stollmann and Sturm, whose aim is to capture the "geometry" of the underlying space out of the Dirichlet form of a process living on that space, suggests a notion of distance associated to a Dirichlet form. More precisely, under some mild hypothesis on the regularity of the Dirichlet form, they provide a distance in the wide sense, called intrinsic metric, which is interpreted as an extension of Riemannian  geometry applicable to non differential structures. We prove  that the needed mild hypotheses are satisfied but that the associated intrinsic metric unfortunately vanishes, thus showing that renormalization theory remains out of reach of  the metric aspect  of Dirichlet forms.

#### Article information

Source
Electron. J. Probab., Volume 19 (2014), paper no. 96, 25 pp.

Dates
Accepted: 16 October 2014
First available in Project Euclid: 4 June 2016

https://projecteuclid.org/euclid.ejp/1465065738

Digital Object Identifier
doi:10.1214/EJP.v19-2950

Mathematical Reviews number (MathSciNet)
MR3272329

Zentralblatt MATH identifier
1334.60175

Subjects
Primary: 60G60: Random fields

Rights

#### Citation

Rhodes, Rémi; Garban, Christophe; Vargas, Vincent. On the heat kernel and the Dirichlet form of Liouville Brownian motion. Electron. J. Probab. 19 (2014), paper no. 96, 25 pp. doi:10.1214/EJP.v19-2950. https://projecteuclid.org/euclid.ejp/1465065738

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