Published online by Cambridge University Press: 04 November 2019
We study a rough differential equation driven by fractional Brownian motion with Hurst parameter $H$$(1/4<H\leqslant 1/2)$. Under Hörmander’s condition on the coefficient vector fields, the solution has a smooth density for each fixed time. Using Watanabe’s distributional Malliavin calculus, we obtain a short time full asymptotic expansion of the density under quite natural assumptions. Our main result can be regarded as a “fractional version” of Ben Arous’ famous work on the off-diagonal asymptotics.
The first author was partially supported by JSPS KAKENHI Grant Number JP15K04922. The second author was partially supported by JSPS KAKENHI Grant Number JP17K14202.