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ЖУРНАЛЫ // Symmetry, Integrability and Geometry: Methods and Applications // Архив

SIGMA, 2025, том 21, 107, 48 стр. (Mi sigma2223)

A-Type Open ${\rm SL}(2,\mathbb{C})$ Spin Chain

Pavel V. Antonenkoab, Sergey È. Derkachovb, Pavel A. Valinevichb

a Leonhard Euler International Mathematical Institute, Pesochnaya nab. 10, 197022 St. Petersburg, Russia
b Saint-Petersburg Department of Steklov Mathematical Institute of Russian Academy of Sciences, Fontanka 27, 191023 St. Petersburg, Russia

Аннотация: For the noncompact open ${\rm SL}(2, \mathbb{C})$ spin chain, the eigenfunctions of the special matrix element of monodromy matrix are constructed. The key ingredients of the whole construction are local Yang–Baxter $\mathcal{R}$-operators, $Q$-operator and raising operators obtained by reduction from the $Q$-operator. The calculation of various scalar products and the proof of orthogonality are based on the properties of $Q$-operator and demonstrate its hidden role. The symmetry of eigenfunctions with respect to reflection of the spin variable $s \to 1-s$ is established. The Mellin–Barnes representation for eigenfunctions is derived and equivalence with initial coordinate representation is proved. The transformation from one representation to another is grounded on the application of $A$-type Gustafson integral generalized to the complex field.

Ключевые слова: open spin chain, principal series representations, Mellin–Barnes integrals.

MSC: 81R12, 17B80, 33C70

Поступила: 13 августа 2025 г.; в окончательном варианте 8 декабря 2025 г.; опубликована 21 декабря 2025 г.

Язык публикации: английский

DOI: 10.3842/SIGMA.2025.107


ArXiv: 2507.09568


© МИАН, 2026