Averaging the operators for a large number of clusters: Phase transitions
    
    
  
  
  
      
      
      
        
Teoretičeskaâ i matematičeskaâ fizika, Tome 125 (2000) no. 2, pp. 297-314
    
  
  
  
  
  
    
      
      
        
      
      
      
    Voir la notice de l'article provenant de la source Math-Net.Ru
            
              			We develop the theory of averaging the operators in a Fock space, introduced in our previous papers. We find the algebra of mean operators. We introduce the quantum entropy and quantum free energy using the function $f(z)=z\ln(z)$ of the mean unit operator (the “measure” of mean operators). Such a “quantum thermodynamics” determines the temperature dependence of the critical speed (“the Landau criterion”) and the temperature distribution at which the speed of a superfluid system is nonzero even at zero temperature. We generalize the consideration to the case where sparsely distributed bosons form clusters.
			
            
            
            
          
        
      @article{TMF_2000_125_2_a7,
     author = {V. P. Maslov},
     title = {Averaging the operators for a large number of clusters: {Phase} transitions},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {297--314},
     publisher = {mathdoc},
     volume = {125},
     number = {2},
     year = {2000},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_2000_125_2_a7/}
}
                      
                      
                    V. P. Maslov. Averaging the operators for a large number of clusters: Phase transitions. Teoretičeskaâ i matematičeskaâ fizika, Tome 125 (2000) no. 2, pp. 297-314. http://geodesic.mathdoc.fr/item/TMF_2000_125_2_a7/
