Few-electron physics in single- and double quantum dots in carbon nanotubes

We study the few-electron eigenspectrum of single- and double quantum dots in carbon-nanotubes. The interplay between spin-orbit coupling and electron-electron interaction strongly modifies the two-particle spectrum. In particular, we find a transition to a spin- and valley polarized ground state at small magnetic fields even for a single quantum dot. We discuss manifestations of this break-down of the constant interaction model in the transport characteristics of double dots, and analyze when Pauli-blockade of the current can occur.