{"title":"Decay of Solutions of Nonlinear Dirac Equations","authors":"Sebastian Herr, Christopher Maulén, Claudio Muñoz","doi":"10.1007/s00220-026-05597-2","DOIUrl":"10.1007/s00220-026-05597-2","url":null,"abstract":"<div><p>We study the long-time behavior of small and large solutions to a broad class of nonlinear Dirac-type equations. Our results are classified in 1D massless and massive cases, 3D general and <i>n</i>-dimensional in generality. In the 1D massless case, we prove that any globally defined <span>(L^2)</span> solution converges to zero as time tends to infinity within a spatial region expanding at a rate proportional to <span>( t log ^{-2} t)</span>. This result holds without assumptions on the smallness of initial data or specific power of nonlinearity, ruling out the existence of standing breather-like or solitary wave structures in this regime. In the 1D massive case, solitary waves are known to exist. Introducing new virial identities adapted to Dirac’s distinctive algebra, we prove that there are “holomorphic” odd nonlinearities under which globally defined small odd solutions decay to zero on spatial compact sets as time tends to infinity. This result is extended to the 3D case under boundedness of the <span>(H^1)</span> norm but without requiring the parity condition on the data, giving decay proofs for an important class of nonlinear Dirac models, and opening the door to the future use of virial identities to prove asymptotic stability of well-chosen Dirac solitary waves. Finally, in higher dimensions <span>( n ge 1)</span>, we prove the <span>(L^2)</span> decay for global solutions of nonlinear Dirac equations in the “exterior light-cone” region. This confirms the non-existence of breathers and other solutions propagating faster than the speed of light. Our proofs rely on carefully constructed weighted virial identities.</p></div>","PeriodicalId":522,"journal":{"name":"Communications in Mathematical Physics","volume":"407 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147614782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Stability of Force-Free Fields in Weak Ideal Limits of Leray–Hopf Solutions II: Nonlinear Force-Free Fields","authors":"Ken Abe","doi":"10.1007/s00220-026-05613-5","DOIUrl":"10.1007/s00220-026-05613-5","url":null,"abstract":"<div><p>We study the ideal magnetohydrodynamics (MHD) equations in <span>(mathbb {R}^{3})</span> under the asymptotic condition <span>((u,B)rightarrow (u_{infty }, B_{infty }) )</span> as <span>(|x|rightarrow infty )</span> for constant vectors <span>(u_{infty })</span>, <span>(B_{infty }in mathbb {R}^{3})</span>. We prove that the explicit traveling wave solution given by <span>(u=u_{infty })</span> and <span>(B=U_{C}(x-u_{infty }t))</span>, where <span>(U_{C})</span> is an axisymmetric nonlinear force-free field with swirl, is orbitally stable in weak ideal limits of axisymmetric Leray–Hopf solutions to the viscous and resistive MHD equations.</p></div>","PeriodicalId":522,"journal":{"name":"Communications in Mathematical Physics","volume":"407 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147612873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Intermittent Two-Point Dynamics at the Transition to Chaos for Random Circle Endomorphisms","authors":"V. P. H. Goverse, A. J. Homburg, J. S. W. Lamb","doi":"10.1007/s00220-026-05565-w","DOIUrl":"10.1007/s00220-026-05565-w","url":null,"abstract":"<div><p>We establish the existence of intermittent two-point dynamics and infinite stationary measures for a class of random circle endomorphisms with zero Lyapunov exponent, as a dynamical characterisation of the transition from synchronisation (negative Lyapunov exponent) to chaos (positive Lyapunov exponent).\u0000</p></div>","PeriodicalId":522,"journal":{"name":"Communications in Mathematical Physics","volume":"407 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00220-026-05565-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147612876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Twisted Quantum Affine Algebras and Equivariant (phi )-Coordinated Modules for Quantum Vertex Algebras","authors":"Naihuan Jing, Fei Kong, Haisheng Li, Shaobin Tan","doi":"10.1007/s00220-026-05621-5","DOIUrl":"10.1007/s00220-026-05621-5","url":null,"abstract":"<div><p>This paper is to establish a natural connection of quantum affine algebras with quantum vertex algebras. Among the main results, we construct a family of <span>(hbar )</span>-adic quantum vertex algebras <span>(V_L[[hbar ]]^{eta })</span> as deformations of the lattice vertex algebras <span>(V_L)</span>, and establish a natural connection between twisted (and untwisted) quantum affine algebras of type <i>A</i>, <i>D</i>, or <i>E</i> and equivariant <span>(phi )</span>-coordinated quasi modules for <span>(V_L[[hbar ]]^{eta })</span> with certain specialized <span>(eta )</span>.</p></div>","PeriodicalId":522,"journal":{"name":"Communications in Mathematical Physics","volume":"407 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147612878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Colin Guillarmou, Trishen S. Gunaratnam, Vincent Vargas
{"title":"2d Sinh-Gordon Model on the Infinite Cylinder","authors":"Colin Guillarmou, Trishen S. Gunaratnam, Vincent Vargas","doi":"10.1007/s00220-026-05588-3","DOIUrl":"10.1007/s00220-026-05588-3","url":null,"abstract":"<div><p>For <span>(R>0)</span>, we give a rigorous probabilistic construction on the cylinder <span>(mathbb {R}times (mathbb {R}/ (2pi R mathbb {Z})))</span> of the (massless) Sinh-Gordon model. In particular we define the <i>n</i>-point correlation functions of the model and show that these exhibit a scaling relation with respect to <i>R</i>. The construction, which relies on the massless Gaussian Free Field, is based on the spectral analysis of a quantum operator associated to the model. Using the theory of Gaussian multiplicative chaos, we prove that this operator has discrete spectrum and a strictly positive ground state.</p></div>","PeriodicalId":522,"journal":{"name":"Communications in Mathematical Physics","volume":"407 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147614772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Approximate Quantum 3-Colorings of Graphs and the Quantum Max 3-Cut Problem","authors":"Samuel J. Harris","doi":"10.1007/s00220-026-05585-6","DOIUrl":"10.1007/s00220-026-05585-6","url":null,"abstract":"<div><p>We prove that, to each synchronous non-local game <span>(mathcal {G}=(I,O,lambda ))</span> with <span>(|I|=n)</span> and <span>(|O|=m ge 3)</span>, there is an associated graph <span>(G_{lambda })</span> for which approximate winning strategies for the game <span>(mathcal {G})</span> and the 3-coloring game for <span>(G_{lambda })</span> are preserved. That is, using a similar graph to previous work of the author (Ann Henri Poincaré, 2024), any synchronous strategy for <span>(text {Hom}(G_{lambda },K_3))</span> that wins the game with probability <span>(1-varepsilon )</span> with respect to the uniform probability distribution on the edges, yields a strategy in the same model that wins the game <span>(mathcal {G})</span> with respect to the uniform distribution with probability at least <span>(1-h(n,m)varepsilon ^{frac{1}{2}})</span>, where <i>h</i> is a polynomial in <i>n</i> and <span>(2^m)</span>. As an application, we prove that the gapped promise problem for quantum 3-coloring is undecidable, with doubly inverse exponential gap. Moreover, we show that the problem of determining whether a synchronous non-local game <span>(mathcal {G})</span> has quantum value 1 or quantum value less than <span>(1-varepsilon )</span>, when promised that one of those occur, can be reduced to a related promise problem for the non-commutative Max-3-Cut of a graph |<i>E</i>|, giving a partial answer to a problem posed by Culf et al. (Approximation algorithms for noncommutative constraint satisfaction problems, 2014. arXiv:2312.16765), along with evidence for a sharp computability gap in the non-commutative Max-3-Cut problem. This also gives evidence that the non-commutative (respectively, commuting operator framework) Max-3-Cut of a graph is uncomputable. All of these results avoid use of the unique games conjecture.</p></div>","PeriodicalId":522,"journal":{"name":"Communications in Mathematical Physics","volume":"407 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147611956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Non-perturbative Isospectrality for Quasi-periodic Gasymov-Type Potentials","authors":"Jiawei He, Xueyin Wang, Zhenfu Wang","doi":"10.1007/s00220-026-05611-7","DOIUrl":"10.1007/s00220-026-05611-7","url":null,"abstract":"<div><p>For quasi-periodic Schrödinger operators with small Gasymov-type potentials and arbitrary irrational frequencies, we establish a complete spectral characterization: the spectrum coincides with that of the discrete free Laplacian. Our result is non-perturbative in the sense that the smallness condition is independent of the frequency. Furthermore, we prove the absence of both residual and point spectra, thereby establishing purely continuous spectrum. The proof combines Avila’s global theory, non-perturbative almost reducibility, and Green’s function estimates.</p></div>","PeriodicalId":522,"journal":{"name":"Communications in Mathematical Physics","volume":"407 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147612874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Parallel Surface Defects, Hecke Operators, and Quantum Hitchin System","authors":"Saebyeok Jeong, Norton Lee, Nikita Nekrasov","doi":"10.1007/s00220-026-05603-7","DOIUrl":"10.1007/s00220-026-05603-7","url":null,"abstract":"<div><p>We examine two types of half-BPS surface defects—regular monodromy surface defect and canonical surface defect—in four-dimensional gauge theory with <span>(mathcal {N}=2)</span> supersymmetry and <span>(Omega _{varepsilon _1,{varepsilon }_2})</span>-background. Mathematically, we investigate integrals over the moduli spaces of parabolic framed sheaves over <span>(mathbb {P}^2)</span>. Using analytic methods of <span>(mathcal {N}=2)</span> theories, we demonstrate that the former gives a twisted <span>(mathcal {D})</span>-module on <span>(text {Bun}_{G_{mathbb {C}}})</span> while the latter acts as a Hecke operator. In the limit <span>({varepsilon }_2 rightarrow 0)</span>, the cluster decomposition implies the Hecke eigensheaf property for the regular monodromy surface defect. The eigenvalues are given by the opers associated to the canonical surface defect. We derive, in our <span>(mathcal {N}=2)</span> gauge theoretical framework, that the twisted <span>(mathcal {D})</span>-modules assigned to the opers in the geometric Langlands correspondence represent the spectral equations for quantum Hitchin integrable system. A duality to topologically twisted four-dimensional <span>(mathcal {N}=4)</span> theory is discussed, in which the two surface defects are mapped to Dirichlet boundary and ’t Hooft line defect. This is consistent with earlier works on the <span>(mathcal {N}=4)</span> theory approach to the geometric Langlands correspondence.</p></div>","PeriodicalId":522,"journal":{"name":"Communications in Mathematical Physics","volume":"407 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147606625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"A Classification of Intrinsic Ergodicity for Recognisable Random Substitution Systems","authors":"P. Gohlke, A. Mitchell","doi":"10.1007/s00220-026-05602-8","DOIUrl":"10.1007/s00220-026-05602-8","url":null,"abstract":"<div><p>We study a class of dynamical systems generated by random substitutions, which contains both intrinsically ergodic systems and instances with several measures of maximal entropy. In this class, we show that the measures of maximal entropy are classified by invariance under an appropriate symmetry relation. All measures of maximal entropy are fully supported and they are generally not Gibbs measures. We prove that there is a unique measure of maximal entropy if and only if an associated Markov chain is ergodic in inverse time. This Markov chain has finitely many states and all transition matrices are explicitly computable. Thereby, we obtain several sufficient conditions for intrinsic ergodicity that are easy to verify. A practical way to compute the topological entropy in terms of inflation words is extended from previous work to a more general geometric setting.</p></div>","PeriodicalId":522,"journal":{"name":"Communications in Mathematical Physics","volume":"407 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13013267/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147519713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Internal Waves in a 2D Subcritical Channel","authors":"Zhenhao Li, Jian Wang, Jared Wunsch","doi":"10.1007/s00220-026-05591-8","DOIUrl":"10.1007/s00220-026-05591-8","url":null,"abstract":"<div><p>We analyze the scattering of linear internal waves in a two dimensional channel with subcritical bottom topography. We construct the scattering matrix for the internal wave problem in a channel with straight ends, mapping incoming data to outgoing data; this operator turns out to differ by a smoothing operator from the pullback by the “bounce map” for boundary data obtained by ray-tracing. As a consequence we obtain unique solvability of the inhomogeneous stationary scattering problem subject to an appropriate outgoing radiation condition.</p></div>","PeriodicalId":522,"journal":{"name":"Communications in Mathematical Physics","volume":"407 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}