Soliton Condensates for the Focusing Nonlinear Schrödinger Equation: a Non-Bound State Case

• Veröffentlicht in: Symmetry, Integrability and Geometry: Methods and Applications
• Datum: 2024
• Hauptverfasser: Tovbis, Alexander, Wang, Fudong
• Format: Artikel
• Sprache: Englisch
• Veröffentlicht: Інститут математики НАН України 2024
• Online Zugang: https://nasplib.isofts.kiev.ua/handle/123456789/212350
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Zitieren: Soliton Condensates for the Focusing Nonlinear Schrödinger Equation: a Non-Bound State Case. Alexander Tovbis and Fudong Wang. SIGMA 20 (2024), 070, 26 pages

In this paper, we study the spectral theory of soliton condensates - a special limit of soliton gases - for the focusing NLS (fNLS). In particular, we analyze the kinetic equation for the fNLS circular condensate, which represents the first example of an explicitly solvable fNLS condensate with nontrivial large-scale space-time dynamics. Solution of the kinetic equation was obtained by reducing it to Whitham-type equations for the endpoints of spectral arcs. We also study the rarefaction and dispersive shock waves for circular condensates, as well as calculate the corresponding average conserved quantities and the kurtosis. We want to note that one of the main objects of the spectral theory - the nonlinear dispersion relations - is introduced in the paper as some special large genus (thermodynamic) limit of the Riemann bilinear identities that involve the quasimomentum and the quasienergy meromorphic differentials.