12 pages.-- PACS numbers: 73.63.Nm, 71.70.Ej, 71.15.Mb, 71.70.Gm.-- Final full-text version of the paper available at: http://dx.doi.org/10.1103/PhysRevB.76.115306.Within the noncollinear local spin-density approximation, we have studied the ground state structure of a parabolically confined quantum wire submitted to an in-plane magnetic field, including both Rashba and Dresselhaus spin-orbit interactions. We have explored a wide range of linear electronic densities in the weak (strong) coupling regimes that appear when the ratio of spin-orbit to confining energy is small (large). These results are used to obtain the conductance of the wire. In the strong coupling limit, the interplay between the applied magnetic field irrespective of the in-plane direction, the exchange-correlation energy, and the spin-orbit energy produces anomalous plateaus in the conductance vs linear density plots that are otherwise absent, or washes out plateaus that appear when the exchange-correlation energy is not taken into account.This work has been performed under Grants No.
FIS2005-01414 and No. FIS2005-02796 from DGI (Spain), Grant No. 2005SGR00343 from Generalitat de Catalunya, and under Grant No. INFN07-30 from the Italian INFN-Spanish DGI agreement.http://dx.doi.org/10.1103/PhysRevB.76.11530
