Harmonic oscillator in twisted Moyal plane: eigenvalue problem and relevant properties

The paper reports on a study of a harmonic oscillator (ho) in the twisted Moyal space, in a well defined matrix basis, generated by the vector fields $X_{a}=e_{a}^{\mu}(x)\partial_{\mu}=(\delta_{a}^{\mu}+\omega_{ab}^{\mu}x^{b})\partial_{\mu}$, which induce a dynamical star product. The usual multiplication law can be hence reproduced in the $\omega_{ab}^{\mu}$ null limit. The star actions of creation and annihilation functions are explicitly computed. The ho states are infinitely degenerate with energies depending on the coordinate functions.