Saratov Fall Meeting: Laser Physics, Photonic Technologies, and Molecular Modeling

Thermal entanglement of two atoms with dipole-dipole and Ising interactions

Eugene K. Bashkirov

Published Apr 29, 2022• 3 citations

Abstract

In this paper, we investigated the entanglement dynamics between two two-level natural or artificial atoms interacting with a thermal one-mode field of lossless cavity taking into account the direct dipole-dipole and Ising coupling. We obtained the exact solution for time-dependent density matrix and calculated atom-atom negativity. The results showed that for dipole-uncoupled atoms and resonant atoms-field interaction the entanglement greatly enhances with Ising coupling increasing. In contrast, for model with non-zero detuning the Ising coupling has almost no effect on the degree of entanglement. We also derived that for resonant interaction and dipole-coupled atoms the anti-Ferromagnetic coupling produces a slightly higher degree of entanglement in comparison with the Ferromagnetic coupling. For entangled initial atomic states we obtained that Ising coupling interaction has effect on entanglement behavior only for a model with large detuning values.

DOI: 10.1117/12.2625842

Related papers

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

Евгений Константинович Башкиров

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.

Physics of Wave Processes and Radio SystemsSep 27, 20201 citation

Entanglement of two dipole-coupled qubits interacting with a detuned cavity thermal field

Eugene K. Bashkirov

This paper studies the entanglement properties in a system of two dipole-coupled natural or artificial two-level atoms not-resonantly interacting with an intensive single-mode thermal field for coherent initial atomic states. The results show that the entanglement is weaken due to the initial atomic coherence for model with detuning in contrast to the model with resonant atom-field interaction. For non-dissipative model under consideration the detuning results also in decreasing of the atom-atom entanglement in time for separable initial atomic state and intensive cavity thermal field.

Jun 3, 20193 citations

Influence of dipole-dipole interaction and detuning on entanglement dynamics in two-atom Jaynes-Cummings model

Anatoly Vorobiev, Eugene K. Bashkirov

We have investigated the dynamics of entanglement of two identical qubits non-resonantly interacting with one mode of a thermal electromagnetic field in a lossless cavity in the presence of a direct dipole-dipole interaction. On the basis of the exact solution the evolution equation the negativity for qubits has been found. Numerical simulation of the negativity for various model parameters has been carried out. It has been shown that the interaction of qubits with the cavity thermal field can lead to their entanglement. It has been established that the detuning and dipole-dipole interaction of qubits can be used to manipulate and control the degree of their entanglement.

Saratov Fall Meeting: Laser Physics, Photonic Technologies, and Molecular ModelingApr 26, 20180 citations

Entanglement between atom interacting with a thermal field of a lossless cavity and a free atom

Eugene K. Bashkirov, Башкиров Е. К, Maria O. Guslyannikova +1 more

In the present paper we studied the entanglement of a quantum system consisting of two dipole-coupled two-level atoms, one of which interacts with one-mode thermal field in a lossless cavity, and another is outside a cavity. We obtained the analytical expression of the atom-atom negativity for separable initial atomic state and investigated the influence of a detuning between the atom and the field frequencies and direct dipole-dipole interaction on an atom-atom entanglement. We derived that detuning might cause high atom-atom entanglement in the presence of the dipole-dipole interaction. We also showed that the detuning and dipole-dipole interaction are an effective mechanisms for control and operation of the atomic entanglement.

Physics of Wave Processes and Radio SystemsDec 15, 20180 citations

Dynamics of entanglement of atoms with two-photon transitions induced by a thermal field

Eugene K. Bashkirov

In this paper, we investigate the entanglement between two two-level atoms non-resonantly in-teracting with a thermal field of a lossless one-mode resonator via degenerate two-photon transi-tions. On the basis of the exact solution of the time-dependent density matrix we calculate the negativity as a measure of atomic entanglement. We show that for separable initial atomic states a slight atom-field detuning may generate the high amount of atom-atom entanglement. The re-sults also show that for non-resonant atom-field interaction the entanglement induced by nonlin-ear two-photon interaction is smaller than that induced by one-photon interaction in contrast to the resonant interaction situation. For a Bell-type entangled initial atomic state we obtain that if the detuning increases, there is an appreciable decrease in the amplitudes of the negativity oscilla-tions. The results also show that elimination of the sudden death of entanglement for non-resonant two-photon atom-field interaction may take place.

Computer OpticsApr 1, 20205 citations

Entanglement Between Qubits Interacting with Thermal Field

Eugene K. Bashkirov, Michail S. Mastyugin

We have investigated the entanglement between two dipole coupled two-level artificial atoms (superconducting qubits, ion, spins etc.). The model, in which only one atom is trapped in an lossless cavity and interacts with single-mode thermal field, and the other one can be spatially moved freely outside the cavity has been carried out. We have considered the effect of the atomic coherence on the entanglement behavior. We have shown that a thermal field might cause high entanglement between the atoms both for coherent and incoherent initial atomic states only for small values of cavity mean photon number. We have also derived that the degree of entanglement is weakly dependent on the strength of dipole-dipole interaction for coherent initial states. In the considered model the atoms would get entangled even when both atoms are initially in the excited state.

EPJ Web of ConferencesJan 1, 20152 citations