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<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" article-type="research-article" dtd-version="1.2" xml:lang="en"><front><journal-meta><journal-id journal-id-type="publisher-id">Journal of Samara State Technical University, Ser. Physical and Mathematical Sciences</journal-id><journal-title-group><journal-title xml:lang="en">Journal of Samara State Technical University, Ser. Physical and Mathematical Sciences</journal-title><trans-title-group xml:lang="ru"><trans-title>Вестник Самарского государственного технического университета. Серия «Физико-математические науки»</trans-title></trans-title-group></journal-title-group><issn publication-format="print">1991-8615</issn><issn publication-format="electronic">2310-7081</issn><publisher><publisher-name xml:lang="en">Samara State Technical University</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">516565</article-id><article-id pub-id-type="doi">10.14498/vsgtu2040</article-id><article-id pub-id-type="edn">ZPKXMD</article-id><article-categories><subj-group subj-group-type="toc-heading" xml:lang="en"><subject>Differential Equations and Mathematical Physics</subject></subj-group><subj-group subj-group-type="toc-heading" xml:lang="ru"><subject>Дифференциальные уравнения и математическая физика</subject></subj-group><subj-group subj-group-type="article-type"><subject>Research Article</subject></subj-group></article-categories><title-group><article-title xml:lang="en">Dynamics of a thermal entanglement in the not-resonant three-qubit Tavis-Cummings model with Kerr nonlinearity</article-title><trans-title-group xml:lang="ru"><trans-title>Динамика теплового перепутывания в нерезонансной трехкубитной модели Тависа-Каммингса с керровской нелинейностью</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-1098-0300</contrib-id><name-alternatives><name xml:lang="en"><surname>Bagrov</surname><given-names>Alexander R.</given-names></name><name xml:lang="ru"><surname>Багров</surname><given-names>Александр Романович</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Masters' Student; Dept. of General and Theoretical Physics</p></bio><bio xml:lang="ru"><p>магистрант; каф. общей и теоретической физики</p></bio><email>alexander.bagrov00@mail.ru</email><uri>https://www.mathnet.ru/person194194</uri><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0001-8682-4956</contrib-id><name-alternatives><name xml:lang="en"><surname>Bashkirov</surname><given-names>Eugene K.</given-names></name><name xml:lang="ru"><surname>Башкиров</surname><given-names>Евгений Константинович</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Dr. Phys. &amp; Math. Sci., Professor; Professor; Dept. of General and Theoretical Physics</p></bio><bio xml:lang="ru"><p>доктор физико-математических наук, профессор; профессор; каф. общей и теоретической физики</p></bio><email>bashkirov.ek@ssau.ru</email><uri>https://www.mathnet.ru/person23894</uri><xref ref-type="aff" rid="aff1"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">Samara National Research University</institution></aff><aff><institution xml:lang="ru">Самарский национальный исследовательский университет имени академика С.П. Королева</institution></aff></aff-alternatives><pub-date date-type="pub" iso-8601-date="2024-09-02" publication-format="electronic"><day>02</day><month>09</month><year>2024</year></pub-date><volume>28</volume><issue>1</issue><issue-title xml:lang="en"/><issue-title xml:lang="ru"/><fpage>7</fpage><lpage>28</lpage><history><date date-type="received" iso-8601-date="2023-06-30"><day>30</day><month>06</month><year>2023</year></date><date date-type="accepted" iso-8601-date="2023-08-11"><day>11</day><month>08</month><year>2023</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; 2024, Authors; Samara State Technical University (Compilation, Design, and Layout)</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; 2024, Авторский коллектив; Самарский государственный технический университет (составление, дизайн, макет)</copyright-statement><copyright-year>2024</copyright-year><copyright-holder xml:lang="en">Authors; Samara State Technical University (Compilation, Design, and Layout)</copyright-holder><copyright-holder xml:lang="ru">Авторский коллектив; Самарский государственный технический университет (составление, дизайн, макет)</copyright-holder><ali:free_to_read xmlns:ali="http://www.niso.org/schemas/ali/1.0/"/><license><ali:license_ref xmlns:ali="http://www.niso.org/schemas/ali/1.0/">https://creativecommons.org/licenses/by/4.0</ali:license_ref></license></permissions><self-uri xlink:href="https://journals.eco-vector.com/1991-8615/article/view/516565">https://journals.eco-vector.com/1991-8615/article/view/516565</self-uri><abstract xml:lang="en"><p>In this article, we consider the dynamics of three identical qubits interacting not-resonantly with a thermal field of an ideal resonator with a Kerr medium. We have found the solutions of the Liouville quantum equation for the total density matrix of a system under consideration for the initial separable, biseparable, and genuine entangled states of the qubits and the thermal initial state of the resonator field. By averaging the total density matrix over the variables of the resonator field and the variables of one of the qubits, we found the reduced density matrix of the pair of remaining qubits. Two-qubit density matrices were used to calculate the qubit-qubit negativity. The results showed that detuning and Kerr nonlinearity can greatly enhance the amout of entanglement for initial separable state of a pair of qubits. It is also shown that detuning and a Kerr medium can inhibit the sudden death of entanglement.</p></abstract><trans-abstract xml:lang="ru"><p>Рассматривается динамика трех идентичных кубитов, нерезонансно взаимодействующих с тепловым полем идеального резонатора со средой Керра. Найдены решения квантового временного уравнения Лиувилля для полной матрицы плотности системы из трех кубитов и поля резонатора для начальных сепарабельных, бисепарабельных и истинных перепутанных состояний кубитов и теплового начального состояния поля резонатора. Путем усреднения полной матрицы плотности по переменным поля резонатора и по переменным одного из кубитов найдена редуцированная матрица плотности пары оставшихся кубитов. Проведены вычисления для всех возможных пар кубитов. Двухкубитные матрицы плотности использованы для вычисления параметра перепутывания кубитов — отрицательности пар кубитов. Проведено численное моделирование временной зависимости отрицательности для различных начальных состояний кубитов и параметров модели. Результаты численного моделирования отрицательности пар кубитов показали, что наличие расстройки и керровской нелинейности в случае начального сепарабельного состояния пары кубитов может приводить к существенному увеличению степени их перепутывания. В случае начального перепутанного состояния пары кубитов расстройка и керровская среда могут значительно уменьшить амплитуды осцилляций Раби отрицательности и, соответственно, приводить к существенной стабилизации начального перепутывания кубитов. Показано также, что наличие расстройки и керровской нелинейности может приводить к исчезновению эффекта мгновенной смерти перепутывания кубитов.</p></trans-abstract><kwd-group xml:lang="en"><kwd>qubits</kwd><kwd>quantum Liouville equation</kwd><kwd>thermal field</kwd><kwd>entanglement</kwd><kwd>negativity</kwd><kwd>sudden death of entanglement</kwd><kwd>Kerr medium</kwd><kwd>detuning</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>кубиты</kwd><kwd>квантовое уравнение Лиувилля</kwd><kwd>тепловое поле</kwd><kwd>перепутывание</kwd><kwd>отрицательность</kwd><kwd>эффект мгновенной смерти перепутывания</kwd><kwd>среда Керра</kwd><kwd>расстройка</kwd></kwd-group><funding-group/></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>Buluta I., Ashhab S., Nori F. Natural and artificial atoms for quantum computation // Rep. Prog. Phys., 2011. vol. 74, no. 10, 104401, arXiv: 1002.1871 [quant-ph]. 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