Lacunas in the optical force induced by quantum fluctuations of quasicontinuum of multipole plasmons

TL;DR

This paper explores how quantum fluctuations of multipole plasmons create narrow lacunas in the optical van der Waals force between a nanoparticle and a molecule, revealing complex quantum effects in nanoscale interactions.

Contribution

It provides an exact solution showing how quantum fluctuations induce lacunas in the optical force, highlighting the spectral role of multipole plasmons.

Findings

Force exhibits narrow lacunas at specific distances due to quantum fluctuations.

Spectral features of multipole plasmons determine the lacunas in force.

Dissipation effects are discussed in the context of force behavior.

Abstract

We investigate the force between plasmonic nanoparticle and highly excited two-level system (molecule). Usually van der Waals force between nanoscale electrically neutral systems is monotonic and attractive at moderate and larger distances and repulsive at small distances. In our system, the van der Waals force acting on molecule has optical nature. At moderate distances it is attractive as usual but its strength highly increases in a narrow distance ranges ("lacunas"). We show that quantum fluctuations of (quasi)continuum of multipole plasmons of high, nearly infinite degree altogether form effective environment and determine the interaction force while their spectral peculiarities stand behind the large and narrow lacunas in force. We solve exactly the Hamiltonian problem and discuss the role of the dissipation.