Entanglement of atoms induced by thermal noise in the presence of initial atomic coherence

In this article, author investigated the dynamics of entanglement of two dipole-coupled natural or artificial two-level atoms (qubits) interacting nonresonantly with the intensive one-mode cavity thermal field. Author found an exact solution of the quantum Liouville equation for the full density matrix of the system two atoms + field mode for a coherent initial state of atoms in the dressed states representation. The full system density matrix is used to calculate the two-atom reduced density matrix and to calculate the quantitative criterion for atom-atom entanglement ‒ negativity. The results of computer simulation of the time dependence of negativity showed that in the case of a model with nonresonant interaction, the presence of initial atomic coherence leads to a significant decrease in the maximum degree of atomic entanglement, in contrast to the model with resonant interaction of atoms and a field. For the resonance model, the initial atomic coherence greatly enhances the degree of atomic entanglement.

Optical waveguiding by atomic entanglement in multilevel atom arrays

The optical properties of subwavelength arrays of atoms or other quantum emitters have attracted significant interest recently. For example, the strong constructive or destructive interference of emitted light enables arrays to function as nearly perfect mirrors, support topological edge states, and allow for exponentially better quantum memories. In these proposals, the assumed atomic structure was simple, consisting of a unique electronic ground state. Within linear optics, the system is then equivalent to a periodic array of classical dielectric particles, whose periodicity supports the emergence of guided modes. However, it has not been known whether such phenomena persist in the presence of hyperfine structure, as exhibited by most quantum emitters. Here, we show that waveguiding can arise from rich atomic entanglement as a quantum many-body effect and elucidate the necessary conditions. Our work represents a significant step forward in understanding collective effects in arrays of atoms with realistic electronic structure.

ENTANGLEMENT IN NONDEGENERATE TWO-PHOTON TAVIS - CUMMINGS MODEL

The influence of dipole-dipole interaction on the entanglement between twoatoms with different initial W-like states in Tavis Cummings model withdegenerate two-photon transitions has been investigated. The results show thatthe dipole-dipole interaction leads to the stabilization of atomic entanglement.

ENTANGLEMENT OF TWO DIPOLE-COUPLED ATOMS INTERACTING WITH TWO-MODE THERMAL FIELD IN THE CAVITY WITH HIGH TEMPERATURE

The entanglement of two dipole-coupled atoms with nondegenerate two-photon transitions interacting with two-mode field in lossless cavity has been investigated. The possibility of considerable growth of atomic entanglement is shown in the case of great mean values of thermal photons.