{"title":"A combined generalized Kaup–Newell soliton hierarchy and its hereditary recursion operator and bi-Hamiltonian structure","authors":"Wen-Xiu Ma","doi":"10.1134/S0040577924100027","DOIUrl":"10.1134/S0040577924100027","url":null,"abstract":"<p> On the basis of a specific matrix Lie algebra, we propose a Kaup–Newell-type matrix eigenvalue problem with four potentials and compute an associated soliton hierarchy within the zero-curvature formulation. A hereditary recursion operator and a bi-Hamiltonian structure are presented to show the Liouville integrability of the resulting soliton hierarchy. An illustrative example is a novel model consisting of combined derivative nonlinear Schrödinger equations with two arbitrary constants. </p>","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"221 1","pages":"1603 - 1614"},"PeriodicalIF":1.0,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142518793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Asymptotic solutions of the quantum scattering problem for binary collisions in a system of three charged particles. The inclusion of the dipole interaction","authors":"V. A. Gradusov, S. L. Yakovlev","doi":"10.1134/S0040577924100106","DOIUrl":"10.1134/S0040577924100106","url":null,"abstract":"<p> We construct asymptotic solutions of the binary scattering problem in a three-particle system with the Coulomb interaction; the solutions explicitly take the induced dipole interaction between a free particle and a bound pair of particles into account in each of the possible configurations. Using these solutions, we formulate boundary conditions for the scattering problem in the system of three charged particles for energies that are below the ionization threshold. </p>","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"221 1","pages":"1744 - 1755"},"PeriodicalIF":1.0,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142518702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Gauge transformations between three-component KP and three-component mKP hierarchies","authors":"Lin Sun, Chuanzhong Li, Ming Chen, Wei Liu","doi":"10.1134/S0040577924090058","DOIUrl":"10.1134/S0040577924090058","url":null,"abstract":"<p> We examine the gauge transformations between the three-component Kadomtsev–Petviashvili (KP) hierarchy and the three-component modified Kadomtsev–Petviashvili (mKP) hierarchy. We introduce the auto-Bäcklund transformation of the three-component KP hierarchy and describe the Miura transformation of the three-component KP and mKP hierarchies, that is, <span>(k=0to k=1)</span>. Additionally, the auto-Bäcklund transformation of the three-component mKP hierarchy is also given. This provides more powerful evidence that the gauge transformations generate Miura and auto-Bäcklund transformation on the eigenfunctions of the three-component KP and mKP hierarchies. </p>","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"220 3","pages":"1486 - 1495"},"PeriodicalIF":1.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Quasi-Grammian loop dynamics of a multicomponent semidiscrete short pulse equation","authors":"A. Inam, M. ul Hassan","doi":"10.1134/S0040577924090083","DOIUrl":"10.1134/S0040577924090083","url":null,"abstract":"<p> A semidiscrete short-pulse equation (sdSPE) is presented via a proposed Lax pair. A multicomponent sdSPE is derived using <span>(2^Mtimes 2^M)</span> Lax matrices. The standard binary Darboux transformation (SBDT) is employed by constructing the Darboux matrices from particular eigenvector solutions of the generalized Lax pair not only in the direct space but also in its adjoint space. Explicit expressions of the first- and second-order nontrivial quasi-Grammian loop solutions of the multicomponent sdSPE are computed, by iterating its SBDT. It is also shown that quasi-Grammian loop solutions reduce to the elementary loop solutions by applying reduction of spectral parameters. </p>","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"220 3","pages":"1530 - 1555"},"PeriodicalIF":1.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nonlocal symmetries of two 2-component equations of Camassa–Holm type","authors":"Ziqi Li, Kai Tian","doi":"10.1134/S0040577924090046","DOIUrl":"10.1134/S0040577924090046","url":null,"abstract":"<p> For a <span>(2)</span>-component Camassa–Holm equation, as well as a <span>(2)</span>-component generalization of the modified Camassa–Holm equation, nonlocal infinitesimal symmetries quadratically dependent on eigenfunctions of linear spectral problems are constructed from functional gradients of spectral parameters. With appropriate pseudopotentials, these nonlocal infinitesimal symmetries are prolonged to enlarged systems, and then explicitly integrated to generate symmetry transformations in finite form for the enlarged systems. As implementations of these finite symmetry transformations, some kinds of nontrivial solutions and Bäcklund transformations are derived for both equations. </p>","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"220 3","pages":"1471 - 1485"},"PeriodicalIF":1.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Boundedness-below conditions for a general scalar potential of two real scalar fields and the Higgs boson","authors":"Yisheng Song, Liqun Qi","doi":"10.1134/S0040577924090101","DOIUrl":"10.1134/S0040577924090101","url":null,"abstract":"<p> The most general scalar potential of two real scalar fields and a Higgs boson is a quartic homogeneous polynomial in three variables, which defines a <span>(4)</span>th-order three-dimensional symmetric tensor. Hence, the boundedness of such a scalar potential from below involves the positive (semi-)definiteness of the corresponding tensor. In this paper, we therefore mainly discuss analytic expressions of positive (semi-)definiteness for such a special tensor. First, an analytically necessary and sufficient condition is given to test the positive (semi-)definiteness of a <span>(4)</span>th-order two-dimensional symmetric tensor. Furthermore, by means of such a result, the analytic necessary and sufficient conditions of the boundedness from below are obtained for a general scalar potential of two real scalar fields and the Higgs boson. </p>","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"220 3","pages":"1567 - 1579"},"PeriodicalIF":1.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. M. Mavlonov, Kh. N. Khushvaktov, G. P. Arzikulov, F. H. Haydarov
{"title":"On positive fixed points of operator of Hammerstein type with degenerate kernel and Gibbs measures","authors":"I. M. Mavlonov, Kh. N. Khushvaktov, G. P. Arzikulov, F. H. Haydarov","doi":"10.1134/S0040577924090113","DOIUrl":"10.1134/S0040577924090113","url":null,"abstract":"<p> It is known that translation-invariant Gibbs measures of a model with an uncountable set of spin values can be described by positive fixed points of a nonlinear integral operator of Hammerstein type. Significant results have been obtained on positive fixed points of a Hammerstein-type operator with a degenerate kernel, but the existence of Gibbs measures corresponding to the fixed points have not been proved for constructed kernels. We construct new degenerate kernels of the Hammerstein operator in the context of the theory of Gibbs measures, and show that each positive fixed point of the operator gives a translation-invariant Gibbs measure. </p>","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"220 3","pages":"1580 - 1588"},"PeriodicalIF":1.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Exact solution of the problem of the interaction between a point charge and an insulator with nonlinear susceptibility","authors":"A. A. Belov, M. A. Tintul, P. A. Polyakov","doi":"10.1134/S0040577924090095","DOIUrl":"10.1134/S0040577924090095","url":null,"abstract":"<p> We construct a new exact solution of the problem of a filament placed parallel to the interface between two insulators, one of which has a nonlinear susceptibility. </p>","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"220 3","pages":"1556 - 1566"},"PeriodicalIF":1.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nonlinear dynamics of a two-axis ferromagnet on the semiaxis","authors":"V. V. Kiselev","doi":"10.1134/S0040577924090034","DOIUrl":"10.1134/S0040577924090034","url":null,"abstract":"<p> Using the spectral transform on a torus, we solve the initial–boundary value problem for quasi-one-dimensional excitations in a semibounded ferromagnet, taking the exchange interaction, orthorhombic anisotropy, and magnetostatic fields into account. We used the mixed boundary conditions whose limit cases correspond to free and fully pinned spins at the sample edge. We predict and analyze new types of solitons (moving domain walls and precessing breathers), whose cores are strongly deformed near the sample boundary. At large distances from the sample surface, they take the form of typical solitons in an unbounded medium. We analyze the properties of the reflection of solitons from the sample boundary depending on the degree of spin pinning at the surface. We obtain new conservation laws that guarantee the true boundary conditions to hold when solitons reflect from the sample surface. </p>","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"220 3","pages":"1440 - 1470"},"PeriodicalIF":1.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Periodic solutions of a differential equation with a discontinuous delayed neutral-type feedback","authors":"Yu. A. Yakubiv","doi":"10.1134/S0040577924080117","DOIUrl":"10.1134/S0040577924080117","url":null,"abstract":"<p> We consider a differential equation with a discontinuous delayed neutral-type feedback. In the phase space, we describe classes of initial functions that depend on a number of parameters. We show that in a certain time, solutions return to an analogous class, possibly with other parameters. The analysis of the change in the parameters allows describing periodic solutions and their stability. We show that infinitely many of stable periodic solutions exist. </p>","PeriodicalId":797,"journal":{"name":"Theoretical and Mathematical Physics","volume":"220 2","pages":"1402 - 1409"},"PeriodicalIF":1.0,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}