  We show that the feature of Klein tunneling makes graphene a unique interface
for implementing low control quantum gates between static and mobile qubits. A
ballistic electron spin is considered as the mobile qubit, while the static
qubit is the electronic spin of a quantum dot fixed in a graphene nanoribbon.
Scattering is the low control mechanism of the gate, which, in other systems,
is really difficult to exploit because of both back-scattering and the momentum
dependence of scattering. We find that Klein tunneling enables the
implementation of quasi-deterministic quantum gates regardless of the momenta
or the shape of the wave function of the incident electron. The Dirac equation
is used to describe the system in the one particle approximation with the
interaction between the static and the mobile spins modelled by a Heisenberg
Hamiltonian. Furthermore, we discuss an application of this model to generate
entanglement between two well separated static qubits.
