To build genuine generators of the rotations group in noncommutative quantum mechanics, we show that it is necessary to extend the noncommutative parameter θ to a field operator, which one proves to be only momentum dependent. We find consequently that this field must be obligatorily a dual Dirac monopole in momentum space. Recent experiments in the context of the anomalous Hall effect provide evidence for a monopole in the crystal momentum space. We suggest a connection between the noncommutative field and the Berry curvature in momentum space which is at the origine of the anomalous Hall effect. . Noncommutative gauge theories were also found as being naturally related to string and M-theory [4].In this framework an antisymmetric θ µν parameter usually taken to be constant [5,11] is introduced in the commutation relation of the coordinates in the space time manifold [x µ , x υ ] = iθ µν . This relation leads to the violation of the Lorentz symmetry, a possibility which is intensively studied theoretically and experimentally [12]. Applications of noncommutative theories were also found in condensed matter physics, for instance in the Quantum Hall effect [13? ] and the non-commutative Landau problem [15,16,17] i.e., a quantum particle in the noncommutative plane, coupled to a constant magnetic field with a constant selected θ parameter as usual.In this letter, we generalize the quantum mechanics in non-commutative geometry by promoting the θ parameter with a new field obeying its own field equations. Note that some authors, (for example [18]) introduced a position dependent θ field using a Kontsevich product [19] in the study of gauge theory. Contrary to these approaches we find that the θ field must be momentum dependent.The physical motivations of our work are twofold: (i) For a constant θ field, we show that a quantum particle in a harmonic potential has a behavior similar to a particle in a constant magnetic field θ in standard quantum mechanics, since a paramagnetic term appears in the Hamiltonian. Moreover the particle in the presence of the θ field acquires an effective dual mass in the same way that an electron moving in a periodic potential in solid state physics. Thus it is legitimate to interpret this field like a field having properties of the vacuum.In this context it is natural to extend the theory to a non-constant field. This proposal is strongly enforced by the lack of rotation generators in noncommutative space with a constant θ parameter, i.e. the angular momentum does not satisfy the usual angular momentum algebra. We then show that this θ field is only momentum dependent and that the requirement of the angular momentum algebra, that is the existence of an angular momentum, necessarily imposes a dual Dirac monopole in momentum space field configuration. Thereafter we will intensely use the concept of duality between the quantities defined in momentum space compared with those defined in the position space.(ii) The second motivation comes for recent theoretical works [20] concerning the anomal...