F. Gesztesy et H. Holden, TRACE FORMULAS AND CONSERVATION-LAWS FOR NONLINEAR EVOLUTION-EQUATIONS, Reviews in mathematical physics, 6(1), 1994, pp. 51-95
New trace formulas for linear operators associated with Lax pairs or z
ero-curvature representations of completely integrable nonlinear evolu
tion equations and their relation to (polynomial) conservation laws ar
e established. We particularly study the Korteweg-de Vries equation, t
he nonlinear Schrodinger equation, the sine-Gordon equation, and the i
nfinite Toda lattice though our methods apply to any element of the AK
NS-ZS class. In the KdV context, we especially extend the range of val
idity of the infinite sequence of conservation laws to certain long-ra
nge situations in which the underlying one-dimensional Schrodinger ope
rator has infinitely many (negative) eigenvalues accumulating at zero.
We also generalize inequalities on moments of the eigenvalues of Schr
odinger operators to this long-range setting. Moreover, our contour in
tegration approach naturally leads to higher-order Levinson-type theor
ems for Schrodinger operators on the line.