  We study the Landau levels in curved graphene sheets by measuring the
discrete energy spectrum in the presence of a magnetic field. We observe that
in rippled graphene sheets, the Landau energy levels satisfy the same square
root dependence on the energy quantum number as in flat sheets, $E_n \sim
\sqrt{n}$. Though, we find that the Landau levels in curved sheets are shifted
towards lower energies by an amount proportional to the average spatial
deformation of the sheet. Our findings are relevant for the quantum Hall effect
in curved graphene sheets, which is directly related to Landau quantization.
For the purpose of this study, we develop a new numerical method, based on the
quantum lattice Boltzmann method, to solve the Dirac equation on curved
manifolds, describing the low-energetic states in strained graphene sheets.
