Dual fermionic variables and renormalization group approach to junctions of strongly interacting quantum wires

Making a combined use of bosonization and fermionization techniques, we build nonlocal transformationsbetween dual fermion operators, describing junctions of strongly interacting spinful one-dimensional quantumwires. Our approach allows for trading strongly interacting (in the original coordinates) fermionic Hamiltonians for weakly interacting (in the dual coordinates) ones. It enables us to generalize to the strongly interacting regime the fermionic renormalization group approach to weakly interacting junctions. As a result, on one hand, we areable to pertinently complement the information about the phase diagram of the junction obtained within the bosonization approach; on the other hand, we map out the full crossover of the conductance tensors between any two fixed points in the phase diagram connected by a renormalization group trajectory.