Fokker-Planck Equation of an Euler Scheme

60 Views Asked by At

Consider the overdamped Langevin equation

$$ dX_t= -\nabla V(X_t) dt + dW_t $$

with associated FPE for its density $\rho_\cdot(\cdot):\mathbb{R}\times \mathbb{R}^d\to \mathbb{R}$

$$ \partial_t \rho_t = \text{div}(\nabla \rho_t+\rho_t\nabla V). $$

Now consider the Euler Maruyama approximation with step $\tau$

$$ X^\tau_{n+1}=X^\tau_{n}-\nabla V(X^\tau_{n})\big((n+1)\tau-n\tau\big) + W_{(n+1)\tau }-W_{n\tau} $$

and its interpolation

$$X^\tau_t=X^\tau_n~~\text{for}~t\in [n\tau,(n+1)\tau).$$

My question : is there a FPE associated to the above process?