  To understand the dynamics of loop quantum gravity, the deparametrized model
of gravity coupled to a scalar field is studied in a simple case, where the
graph underlying the spin network basis is one loop based at a single vertex.
The Hamiltonian operator $\hat{H}_v$ is chosen to be graph-preserving, and the
matrix elements of $\hat{H}_v$ are explicitly worked out in a suitable basis.
The non-trivial Euclidean part $\hat{H}_v^E$ of $\hat{H}_v$ is studied in
details. It turns out that by choosing a specific symmetrization of
$\hat{H}_v^E$, the dynamics driven by the Hamiltonian gives a picture of
bouncing evolution. Our result in the model of full loop quantum gravity gives
a significant echo of the well-known quantum bounce in the symmetry-reduced
model of loop quantum cosmology, which indicates a closed relation between
singularity resolution and quantum geometry.
