236 citations · 478 across the 11 of their papers we have counts for
11 papers
Modified Zakharov equations for plasmas with a quantum correction
L. G. Garcia, F. Haas, L. P. L. de Oliveira +1
Quantum Zakharov equations are obtained to describe the nonlinear interaction between quantum Langmuir waves and quantum ion-acoustic waves. These quantum Zakharov equations are ap…
Lie Point Symmetries for Reduced Ermakov Systems
F. Haas, J. Goedert
Reduced Ermakov systems are defined as Ermakov systems restricted to the level surfaces of the Ermakov invariant. The condition for Lie point symmetries for reduced Ermakov systems…
Nyquist method for Wigner-Poisson quantum plasmas
F. Haas, G. Manfredi, J. Goedert
By means of the Nyquist method, we investigate the linear stability of electrostatic waves in homogeneous equilibria of quantum plasmas described by the Wigner-Poisson system. We s…
Dynamical symmetries and the Ermakov invariant
F. Haas, J. Goedert
Ermakov systems possessing Noether point symmetry are identified among the Ermakov systems that derive from a Lagrangian formalism and, the Ermakov invariant is shown to result fro…
Comment on "A note on the construction of the Ermakov-Lewis invariant"
F. Haas, J. Goedert
We show that the basic results on the paper referred in the title [J. Phys. A: Math. Gen. v. 35 (2002) 5333-5345], concerning the derivation of the Ermakov invariant from Noether s…
On the linearization of the generalized Ermakov systems
F. Haas, J. Goedert
A linearization procedure is proposed for Ermakov systems with frequency depending on dynamic variables. The procedure applies to a wide class of generalized Ermakov systems which…