Physics of Wave Processes and Radio SystemsPhysics of Wave Processes and Radio Systems1810-31892782-294XPovolzhskiy State University of Telecommunications and Informatics869110.18469/1810-3189.2021.24.1.9-14Research ArticleInfluence of detuning and Kerr nonlinearity on atom-atom entanglement in the double two-photon Jaynes–Cummings modelZakharovRodion K.<p>1st year postgraduate student of the Department of General and Theoretical Physics, Samara National Research University, Samara, Russia. In 2020, he graduated from the magistracy of the Physics Department of the Samara National Research University. Author of two scientific papers.</p>
<p><em>Research interests</em>: quantum optics and quantum radiophysics, quantum informatics.</p>ssau@ssau.ruBashkirovEvgeny K.<p>Doctor of Physical and Mathematical Sciences, professor of the Department of General and Theoretical Physics, Samara National Research University, Samara, Russia. In 1978, he graduated from the Physics Department of Kuibyshev State University and in 1984 - post graduated from Moscow State University. Author of over 350 scientific papers.</p>
<p><em>Research interests</em>: quantum optics and quantum radiophysics, quantum informatics, theory of nonequilibrium phenomena.</p>bash@samsu.ruhttps://orcid.org/0000-0003-2569-1322Samara National Research University0605202124191406052021Copyright © 2021, Zakharov R., Bashkirov E.2021<p>In this work, the authors investigated the dynamics of entanglement of two identical two-level atoms (qubits) in the framework of the two-photon double Jaynes–Cummings model, taking into account the detuning between atoms and the double frequency of the field modes of the resonators, as well as the Kerr medium in both resonators. The authors derived the time dependence of the negativity parameter for the Bell initial states of the atoms and the vacuum states of the resonator fields. The results showed that detuning and Kerr nonlinearity leads to stabilization of the entanglement for all initial Bell-type atomic states. For some initial atomic entanglement states, the detuning and Kerr environment in the resonators can prevent the effect of sudden death of the atom-atom entanglement.</p>double Jaynes–Cummings modeltwo-level atomsatomic entanglementKerr nonlinearitynegativitydetuningдвойная модель Джейнса – Каммингсадвухуровневые атомыатомная перепутанностькерровская нелинейность отрицательностьрасстройка[Georgescu I.M., Ashhab S., Nori F. Quantum simulation. Rev. Mod. Phys, 2014, vol. 88, pp. 153–186. DOI: https://doi.org/10.1103/RevModPhys.86.153][Buluta I., Ashab S., Nori F. Neutral and artificial atoms for quantum computation. Rep. Prog. Phys, 2011, vol. 74, p. 104401. DOI: https://doi.org/10.1088/0034-4885/74/10/104401][Scully M.O., Zubairy M.S. Quantum Optics. Cambridge: Cambridge University Press, 1997, 630 p.][Bashkirov E.K. Thermal entanglement between a Jaynes–Cummings atom and an isolated atom. Intern. J. Theor. Phys, 2018, vol. 57, no. 12, pp. 3761–3771. DOI: https://doi.org/10.1007/s10773-018-3888-y][Yönac M.Y., Yu T., Eberly J.H. Sudden death of entanglement of two Jaynes–Cummings atoms. J. Phys. B: At. Mol. Opt. Phys, 2006, vol. 39, pp. 621–625. DOI: https://doi.org/10.12693/APhysPolA.125.1069][Yönac M.Y., Yu T., Eberly J.H. Pairwise concurrence dynamics: a four-qubit model. J. Phys. B: At. Mol. Opt. Phys, 2007, vol. 40, pp. 45–59. DOI: https://doi.org/10.1088/0953-4075/40/9/S02][Xie Q., Fang M.-F. Entanglement dynamics of atoms in double Jaynes–Cummings models with Kerr medium. Commun. Theor. Phys, 2010, vol. 54, no. 5, pp. 840–844. DOI: https://doi.org/10.7498/aps.62.110301][Zhu W.-T. et al. Dynamics of two qubits coupled independently to cavities in the ultrastrong coupling regime: analytical results. Chin. Phys. Lett, 2016, vol. 33, no. 5, p. 050302. DOI: https://doi.org/10.1088/0256-307X/33/5/050302][Liao Q. et al. The entanglement dynamics of two atoms in a double two-photon Jaynes–Cummings model. Chinese Journal of Physics, 2010, vol. 51, no. 2, pp. 404–411. DOI: https://doi.org/10.6122/CJP.51.404][Bashkirov E.K., Evseev M.M. The influence of dipole-dipole interaction on entanglement of two superconducting qubits in the framework of double Jaynes–Cummins model. J. Phys.: Conference Ser, 2017, vol. 917, no. 6, p. 062011. DOI: https://doi.org/10.1088/ 1742-6596/917/6/062011][Bashkirov E.K. Entanglement between two dipole-coupled qubits interacting with two independent slightly detuned cavity modes. Intern. J. Theor. Phys, 2019, vol. 58, no. 7, pp. 2346–2356. DOI: https://doi.org/10.1007/s10773-019-04126-3]