Coherent dynamics of three coupled oscillators

M. B. Shirshov, Vladimir Sergeevich Yarunin

Sara Hassoul, Salah Menouar, Hamid Benseridi +1 more

I. Chiorescu, Patrice Bertet, Kouichi Semba +3 more

Radouan Hab-Arrih, Ahmed Jellal, Abdeldjalil Merdaci

We study the dynamics and redistribution of entanglement and coherence in three time-dependent coupled harmonic oscillators. We resolve the Schrödinger equation by using time-dependent Euler rotation together with a linear quench model to obtain the state of vacuum solution. Such state can be translated to the phase space picture to determine the Wigner distribution. We show that its Gaussian matrix [Formula: see text] can be used to directly cast the covariance matrix [Formula: see text]. To quantify the mixedness and entanglement of the state, one uses respectively linear and von Neumann entropies for three cases: fully symmetric, bi-symmetric and fully nonsymmetric. Then we determine the coherence, tripartite entanglement and local uncertainties and derive their dynamics. We show that the dynamics of all quantum information quantities are driven by the Ermakov modes. Finally, we use an homodyne detection to redistribute both resources of entanglement and coherence.

Alexandra Mîrzac, Mihai Macovei

We investigate the quantum dynamics of a quantum oscillator coupled with the most upper state of a three-level Λ-type system. The two transitions of the three-level emitter, possessing orthogonal dipole moments, are coherently pumped with a single or two electromagnetic field sources, respectively. We have found ranges for flexible lasing or cooling phenomena referring to the quantum oscillator’s degrees of freedom. This is due to asymmetrical decay rates and quantum interference effects leading to population transfer among the relevant dressed states of the emitter’s subsystem with which the quantum oscillator is coupled. As an appropriate system can be considered a nanomechanical resonator coupled with the most excited state of the three-level emitter fixed on it. Alternatively, if the upper state of the Λ-type system possesses a permanent dipole then it can couple with a cavity electromagnetic field mode which can be in the terahertz domain, for instance. In the latter case, we demonstrate an effective electromagnetic field source of terahertz photons.

Pär Kjellberg, Tõnu Pullerits

In this article the third-order response of an excitonically coupled dimer is studied. The three-pulse photon echo signals were calculated by extracting polarization components from the total polarization in the corresponding phase-matched directions. The total nonlinear response was obtained by numeric propagation of the density matrix, with the exciton-vibrational coupling modeled via Redfield relaxation theory. The full two-dimensional three-pulse photon echo signals and the peak shift were analyzed in terms of the density-matrix dynamics of coherence dephasing and population relaxation. The location of the two-exciton state was found to be essential for proper modeling of the three-pulse photon echo. In particular, an oscillation in the three-pulse photon echo peak shift is found if the two-exciton state is displaced. The oscillations can be related to the dynamics of the one-exciton coherences.