Singular resonance in fluctuation-electromagnetic phenomena during the rotation of a nanoparticle near a surface

TL;DR

This paper demonstrates that a singular resonance can occur in fluctuation-electromagnetic phenomena for a rotating nanoparticle near a surface, significantly enhancing effects like Casimir force and heat generation, with potential nanotechnology applications.

Contribution

It reveals the conditions under which a singular resonance occurs in fluctuation-electromagnetic effects for rotating nanoparticles near surfaces, including the role of multiple scattering and dissipation.

Findings

Resonance occurs at specific particle-surface separations and rotation frequencies.

Fluctuation-electromagnetic effects are strongly enhanced near the resonance.

Casimir force can switch from attraction to repulsion near the resonance.

Abstract

It is shown that in fluctuation-electromagnetic phenomena (Casimir force, Casimir friction, radiative heat generation) for a spherical nanoparticle with a radius $R$ rotating near a surface a singular resonance can occur, near which fluctuation-electromagnetic effects are strongly enhanced even in the presence of dissipation in the system. The resonance takes place at the particle-surface separation $ d <d_0= R[3/4\varepsilon_1''(\omega_1)\varepsilon_2''(\omega_2)]^{1/3}$ (where $\varepsilon_i''(\omega_i)$ is the imaginary part of the dielectric function of a particle or a medium at the surface plasmon or phonon polariton frequency $\omega_i$), when the rotation frequency $\Omega$ coincides with the poles in the photon generation rate at $\Omega\approx \omega_1 + \omega_2$. These poles arise due to the multiple scattering of electromagnetic waves between the particle and the surface under the conditions of the anomalous Doppler effect and they exist even in the presence of dissipation. For $ d <d_0$ in the dependence on the particle rotation frequency the Casimir force can change sign, i.e. the attraction of the particle to the surface is replaced by the repulsion. The obtained results can be important for nanotechnology.