Double transfer through Dirac points in a tunable honeycomb optical lattice Thomas Uehlinger, Daniel Greif, Gregor Jotzu, Leticia Tarruell, Tilman Esslinger, Lei Wang and Matthias Troyer Eur. Phys. J. Special Topics, 217 (2013) 121-133 Published online: 11 March 2013 DOI: 10.1140/epjst/e2013-01761-y