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<article article-type="research-article" dtd-version="1.3" 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" xml:lang="ru"><front><journal-meta><journal-id journal-id-type="publisher-id">vestifm</journal-id><journal-title-group><journal-title xml:lang="ru">Известия Национальной академии наук Беларуси. Серия физико-математических наук</journal-title><trans-title-group xml:lang="en"><trans-title>Proceedings of the National Academy of Sciences of Belarus. Physics and Mathematics Series</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">1561-2430</issn><issn pub-type="epub">2524-2415</issn><publisher><publisher-name>The Republican Unitary Enterprise Publishing House "Belaruskaya Navuka"</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.29235/1561-2430-2021-57-3-353-373</article-id><article-id custom-type="elpub" pub-id-type="custom">vestifm-603</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>ФИЗИКА</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>PHYSICS</subject></subj-group></article-categories><title-group><article-title>Теория Фрадкина частицы со спином 3/2, нерелятивистский предел</article-title><trans-title-group xml:lang="en"><trans-title>Spin 3/2 particle: Fradkin theory, nonrelativistic approximation</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Ивашкевич</surname><given-names>А. В.</given-names></name><name name-style="western" xml:lang="en"><surname>Ivashkevich</surname><given-names>A. V.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Ивашкевич Алина Валентиновна – магистрант</p><p>пр. Независимости, 68-2, 220072, г. Минск</p></bio><bio xml:lang="en"><p>Alina V. Ivashkevich – Undergraduate</p><p>68-2, Nezavisimosti Ave., 220072, Minsk</p></bio><email xlink:type="simple">ivashkevich.alina@yandex.by</email><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Василюк</surname><given-names>О. А.</given-names></name><name name-style="western" xml:lang="en"><surname>Vasiluyk</surname><given-names>O. A.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Василюк Ольга Александровна – преподаватель</p><p>бульвар  Космонавтов, 21, 224016, г. Брест</p></bio><bio xml:lang="en"><p>Olga A. Vasiluyk – Teacher</p><p>21, boulevard Kosmonavtov, 224016, Brest</p></bio><email xlink:type="simple">olya.vasiluyk.97@yandex.by</email><xref ref-type="aff" rid="aff-2"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Овсиюк</surname><given-names>Е. М.</given-names></name><name name-style="western" xml:lang="en"><surname>Ovsiyuk</surname><given-names>E. M.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Овсиюк Елена Михайловна – кандидат физико-математических наук, доцент, заведующий кафедрой теоретической физики и прикладной информатики</p><p>ул. Студенческая, 28, 247760, г. Мозырь, Гомельская  обл.</p></bio><bio xml:lang="en"><p>Еlena М. Оvsiyuk – Ph. D. (Physics and Mathematics), Associate Professor, Head of the Department of Theoretical Physics and Applied Informatics</p><p>28, Studencheskaya Str., 247760, Mozyr</p></bio><email xlink:type="simple">e.ovsiyuk@mail.ru</email><xref ref-type="aff" rid="aff-3"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Кисель</surname><given-names>В. В.</given-names></name><name name-style="western" xml:lang="en"><surname>Kisel</surname><given-names>V. V.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Кисель Василий Васильевич – кандидат физико математических наук, доцент, доцент кафедры физики</p><p>ул. П. Бровки, 6, 220013, г. Минск</p></bio><bio xml:lang="en"><p>Vasily V. Kisel – Ph. D. (Physics and Mathematics), Associate Professor, Associate Professor of the Department of Physics</p><p>6, P. Brovka Str., 220013, Minsk</p></bio><email xlink:type="simple">vasiliy_bspu@mail.ru</email><xref ref-type="aff" rid="aff-4"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Редьков</surname><given-names>В. М.</given-names></name><name name-style="western" xml:lang="en"><surname>Red’kov</surname><given-names>V. M.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Редьков Виктор Михайлович – доктор физико-математических наук, главный научный сотрудник центра «Фундаментальные взаимодействия и астрофизика»</p><p>пр. Независимости, 68-2, 220072, г. Минск</p></bio><bio xml:lang="en"><p>Viktor M. Red’kov – Dr. Sc. (Physics and  Mathematics), Chief Researcher of the Center “Fundamental Interactions and Astrophysics”</p><p>68-2, Nezavisimosti Ave., 220072, Minsk</p></bio><email xlink:type="simple">redkov@dragon.bas-net.by</email><xref ref-type="aff" rid="aff-1"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>Институт физики им. Б. И. Степанова Национальной академии наук Беларуси</institution></aff><aff xml:lang="en"><institution>B. I. Stepanov Institute of Physics of the National Academy of Sciences of Belarus</institution></aff></aff-alternatives><aff-alternatives id="aff-2"><aff xml:lang="ru"><institution>Брестский государственный университет им. А. С. Пушкина</institution></aff><aff xml:lang="en"><institution>Brest State University named after A. S. Pushkin</institution></aff></aff-alternatives><aff-alternatives id="aff-3"><aff xml:lang="ru"><institution>Мозырский государственный педагогический университет им. И. П. Шамякина</institution></aff><aff xml:lang="en"><institution>Mozyr State Pedagogical University named after I. P. Shamyakin</institution></aff></aff-alternatives><aff-alternatives id="aff-4"><aff xml:lang="ru"><institution>Белорусский государственный университет информатики и радиоэлектроники</institution></aff><aff xml:lang="en"><institution>Belarusian State University of Informatics and Radioelectronics</institution></aff></aff-alternatives><pub-date pub-type="collection"><year>2021</year></pub-date><pub-date pub-type="epub"><day>07</day><month>10</month><year>2021</year></pub-date><volume>57</volume><issue>3</issue><fpage>353</fpage><lpage>373</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Ивашкевич А.В., Василюк О.А., Овсиюк Е.М., Кисель В.В., Редьков В.М., 2021</copyright-statement><copyright-year>2021</copyright-year><copyright-holder xml:lang="ru">Ивашкевич А.В., Василюк О.А., Овсиюк Е.М., Кисель В.В., Редьков В.М.</copyright-holder><copyright-holder xml:lang="en">Ivashkevich A.V., Vasiluyk O.A., Ovsiyuk E.M., Kisel V.V., Red’kov V.M.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://vestifm.belnauka.by/jour/article/view/603">https://vestifm.belnauka.by/jour/article/view/603</self-uri><abstract><p>Известное уравнение для частицы со спином 3/2, предложенное Паули и Фирцем, основано на использовании волновой функции с трансформационными свойствами вектора-биспинора. Менее известным является уравнение, основанное также на 16-компонентной функции, которое было предложено Фрадкиным. При занулении дополнительного к заряду параметра Λ из уравнения Фрадкина следует уравнение Паули – Фирца. С целью установления физической интерпретации дополнительного параметра Λ в настоящей работе решен вопрос о получении нерелятивистского приближения в теории Фрадкина, при этом учитывается присутствие внешних электромагнитных полей. С использованием метода проективных операторов волновая функция разложена на нерелятивистские большие и малые составляющие, выведено обобщенное нерелятивистское уравнение для 16-компонентной волновой функции. Показывается, что при сохранении в этом уравнении членов первого порядка по параметру Λ после перехода к четырем независимым компонентам нерелятивистской волновой функции возникает обычное нерелятивистское уравнение для теории Паули – Фирца. Если сохранять члены второго порядка по Λ, то возникает 4-компонентное нерелятивистское уравнение с дополнительным членом взаимодействия, причем только с магнитным полем. Это взаимодействие квадратично по компонентам магнитного поля и зависит от шести 4-мерных матриц. Делается вывод, что теория Фрадкина описывает частицу с магнитным квадрупольным моментом.</p></abstract><trans-abstract xml:lang="en"><p>The well-known relativistic wave equation for a spin 3/2 particle proposed by Pauli and Fierz is based on the use of the wave function with the transformation properties of vector-bispinor. Less known is the Fradkin theory based on the vector-bispinor wave function as well. At the vanishing Fradkin parameter Λ, this equation reduces to the Pauli – Fierz equation. To clarify the physical meaning of the additional parameter, in the present paper the nonrelativistic approximation in the Fradkin equation is studied, at this we take into account the presence of external electromagnetic ﬁelds. With the use of the technique of projective operators, we decompose the wave function into big and small constituents, and then derive a generalized nonrelativistic equation for a 16-component wave function. It is shown that when preserving only the terms of ﬁrst order in the Fradkin parameter Λ after transition to 4 independent components of the nonrelativistic wave function there arises the ordinary nonrelativistic equation for the Pauli – Fierz theory without any additional interaction with electromagnetic ﬁelds. When preserving the terms of second order in parameter Λ, we obtain a 4-component nonrelativistic equation with additional interaction; however, only with the magnetic ﬁeld. This interaction is quadratic in magnetic ﬁeld components and governed by six 4-dimensional matrices. So the Fradkin theory may be understood as relevant to a particle with magnetic quadrupole moment.</p></trans-abstract><kwd-group xml:lang="ru"><kwd>спин 3/2</kwd><kwd>теория Паули – Фирца</kwd><kwd>теория Фрадкина</kwd><kwd>проективные операторы</kwd><kwd>нерелятивистское приближение</kwd><kwd>квадрупольный магнитный момент</kwd></kwd-group><kwd-group xml:lang="en"><kwd>spin 3/2</kwd><kwd>Pauli – Fierz theory</kwd><kwd>Fradkin theory</kwd><kwd>projective operators</kwd><kwd>nonrelativistic approximation</kwd><kwd>magnetic quadrupole moment</kwd></kwd-group><funding-group><funding-statement xml:lang="ru">Исследование выполнено при финансовой поддержке Белорусского республиканского фонда фундаментальных исследований (грант № Ф20-РА-007).</funding-statement><funding-statement xml:lang="en">The research was carried out under the ﬁnancial support of the Belarusian Republican Foundation for Fundamental Research (grant no. 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