arXiv subjects

Jan Mathis Giesen

Publications and source records attributed to Jan Mathis Giesen.

4 recordsLinked to original sources

arXiv2026

Resonant excitations via low frequency pumping in driven magnon systems

We analyse resonant excitations of ferromagnetic magnons via microwave pumping using Floquet theory. Special focus is put on driving frequencies that are below the corresponding magnon energy, which can be excited in large parameter regions via parametric resonances. We develop a theoretical framework that analytically predicts the regions of resonances and resonance thresholds in thin films of ferro- and ferri-magnetic materials like YIG as a function of damping, amplitude and frequency. Resonance regions are separated by exceptional points of the quasi-energies and the results are compared with micromagnetic simulations. The corresponding threshold amplitudes can be estimated from a characteristic powerlaw with damping, leading to the possibility of targeted exciatations at selected wavenumbers using low frequency drive.

cond-mat.mes-hall↗

arXiv2026

Tailored dissipation for directional transport in plasmonic ratchets

We present a joint experimental and theoretical study of a ratchet implemented in arra ys of evanescently coupled plasmonic waveguides with tailored losses. In this setup the time-periodic dissipation is the only active mechanism and notably, we find better rectified transport and lower losses in the transmitted signal with increased local dissipation. Using Floquet theory, we uncover a driving regime that allows efficient directional tr ansport for suitable driving frequencies and loss rates, which are linked to linear qu asienergy bands with minimal losses. These regions are separated from non-resonant beh avior by sharp transitions with characteristic exceptional points in the spectrum. Direct experimental observation of the Floquet-dissipative ratchet effect using a comb ination of real- and Fourier-space leakage radiation microscopy is provided.

physics.optics↗

arXiv2025

Tunneling resonances through periodically driven quantum dots

Periodic driving of quantum dots is analyzed as a basis for developing dynamic switching devices. We study transport through periodically modulated energy levels which are coupled to leads via tunneling coefficients. Utilizing Floquet theory a full analytic solution is found in terms of continued fractions, enabling us to efficiently calculate and analyze the transmission through the quantum dot in relevant parameter regimes. By considering levels at higher energy outside the spectrum of the transmitted particles a resonant switching effects is identified, where a very small oscillating control signal on a weakly connected quantum dot can induce perfect transmission. We also find closed form expressions using Bessel functions in the limit of small tunnel couplings. The results predict and explain resonant tunneling in nano-electronic devices as well as in corresponding setups using magnonic systems, photonic waveguides, or ultra-cold gases in optical lattices.

cond-mat.mes-hall↗

arXiv2023

Dissipative Dicke time crystals: an atoms' point of view

We develop and study an atom-only description of the Dicke model with time-periodic couplings between atoms and a dissipative cavity mode. The cavity mode is eliminated giving rise to effective atom-atom interactions and dissipation. We use this effective description to analyze the dynamics of the atoms that undergo a transition to a dynamical superradiant phase with macroscopic coherences in the atomic medium and the light field. Using Floquet theory in combination with the atom-only description we provide a precise determination of the phase boundaries and of the dynamical response of the atoms. From this we can predict the existence of dissipative time crystals that show a subharmonic response with respect to the driving frequency. We show that the atom-only theory can describe the relaxation into such a dissipative time crystal and that the damping rate can be understood in terms of a cooling mechanism.

quant-ph↗