3 papers
math.DS2020
On nomalized differentials on spectral curves associated to thesinh-Gordon equation
Thomas Kappeler, Yannick Widmer
The spectral curve associated with the sinh-Gordon equation on the torus is defined interms of the spectrum of the Lax operator appearing in the Lax pair formulation of the equatio…
math.AP2016
The mKdV and NLS hierarchies revisited
Jan-Cornelius Molnar, Yannick Widmer
The purpose of this paper is to express the entire hierarchy of mKdV vector fields as restrictions of vector fields in the NLS hierarchy. The result is proved using the normal form…
math-ph2015
On the integrability of the sine-Gordon equation
Yannick Widmer
Among other results we show that near the equilibrium point, the Hamiltonian of the sine-Gordon (SG) equation on the circle can be viewed as an element in the Poisson algebra of th…