Levinson formula for perturbed Hill operator
    
    
  
  
  
      
      
      
        
Teoretičeskaâ i matematičeskaâ fizika, Tome 62 (1985) no. 2, pp. 196-209
    
  
  
  
  
  
    
      
      
        
      
      
      
    Voir la notice de l'article provenant de la source Math-Net.Ru
            
              			For a one-dimensional perturbed Hill operator $H$ for which the impurity potential has
a finite first moment, a “Levinson series” is obtained. This series of relationships
generalizes the well-known Levinson formula to the case when there is a periodic
potential. The “Levinson series” is an effective tool for investigating the discrete
spectrum in gaps (forbidden bands). In particular, it is shown that in the case of a reflectionless impurity potential with finite second moment there are no eigenvalues
of the operator $H$ in the distant gaps of the spectrum.
			
            
            
            
          
        
      @article{TMF_1985_62_2_a2,
     author = {N. E. Firsova},
     title = {Levinson formula for perturbed {Hill} operator},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {196--209},
     publisher = {mathdoc},
     volume = {62},
     number = {2},
     year = {1985},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1985_62_2_a2/}
}
                      
                      
                    N. E. Firsova. Levinson formula for perturbed Hill operator. Teoretičeskaâ i matematičeskaâ fizika, Tome 62 (1985) no. 2, pp. 196-209. http://geodesic.mathdoc.fr/item/TMF_1985_62_2_a2/
