Abstract This study pertains to analysing the dynamical behaviour of a floating body undergoing parametric resonances. A simple vertical cylinder, representing classical spar-buoy, is considered, limiting its motion heave and pitch degrees freedom. Its geometry mass distribution are chosen such that 2:1 ratio pitch/roll natural frequency makes spar-buoy prone resonance. The system then studied ...

Voltage-controlled magnetic anisotropy (VCMA) is a low-energy alternative to manipulate the ferromagnetic state, which has been recently also considered in antiferromagnets (AFMs). Here, we theoretically demonstrate that VCMA can be used excite linear and parametric resonant modes easy-axis AFMs with perpendicular anisotropy, thus opening way for an efficient electrical control of N\'eel vector...

We discuss the structure of parametric resonance which occurs in the process of reheating after inflation with two interacting scalar fields. It is found that, for the case of a not too large coupling constant, a quasi-homogeneous part of the second, initially subdominant scalar field may not be neglected due to its stochastic growth during inflation. This fact has strong consequences for the r...

We address the problem of studying the decay of the inflaton field φ to another scalar field χ through parametric resonance in the case of a coupling that involves several decay modes. This amounts to the presence of extra harmonic terms in the perturbation of the χ field dynamics. For the case of two frequencies we compute the geometry of the resonance regions, which is significantly altered d...

We i n vestigate the cosmological perturbation of two-scalar eld model during the reheating phase after innation. Using the exact solution of the perturbation in long-wavelength limit, which is expressed in terms of the background quantities, we analyze the behavior of the metric perturbation. The oscillating innaton eld gives rise to the parametric resonance of the massless scalar eld and this...