We consider metamolecule consisting of bosonic mode correlated with the two-level system: it can be, for example, plasmonic mode interacting with the quantum dot. We focus on the parameter range where all the correlations are strong and of the same o
rder: interaction between bosonic mode correlated with the two-level system, external coherent drive and dissipation. Quantum Monte-Carlo simulations show a fluorescence of this system at dissipation larger than the driving amplitude and strong (by the order of magnitude) narrowing of its spectral line. This effect may be related to kind of a quantum stochastic resonance. We show that the fluorescence corresponds to finite domain over the coherent drive with sharp lower threshold and there is splitting of the Wigner function.
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 repuls
ive 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.
We investigate the dynamics of the spaser-based nanolaser in the strong incoherent pumping regime in the quantum limit when the photon number is the order of unity. We consider the situation where the newly irradiated photon finds itself in the cloud
of earlier irradiated photons that are not thermalized. As the result the entanglement of nanoparticle with quantum dot degrees of freedom in the nanolaser and the lasing intensity increases several times. In fact the nonthermal bath effectively makes the nanolaser more quantum and master equation for the nanolaser density matrix nonlinear and selfconsistent.
We demonstrate that when the frequency of the external field differs from the lasing frequency of an autonomous spaser, the spaser exhibits stochastic oscillations at low field intensity. The plasmon oscillations lock to the frequency of the external
field only when the field amplitude exceeds a threshold value. We find a region of values of the external field amplitude and the frequency detuning (the Arnold tongue) for which the spaser synchronizes with the external wave.
