Some generic aspects of bosonic excitations in disordered systems.

We consider noninteracting bosonic excitations in disordered systems, emphasizing generic features of quadratic Hamiltonians in the absence of Goldstone modes. We discuss relationships between such Hamiltonians and the symmetry classes established for fermionic systems. We examine the density rho(om...

ver descrição completa

Detalhes bibliográficos
Principais autores: Gurarie, V, Chalker, J
Formato: Journal article
Idioma:English
Publicado em: 2002
Descrição
Resumo:We consider noninteracting bosonic excitations in disordered systems, emphasizing generic features of quadratic Hamiltonians in the absence of Goldstone modes. We discuss relationships between such Hamiltonians and the symmetry classes established for fermionic systems. We examine the density rho(omega) of excitation frequencies omega, showing how the universal behavior rho(omega) approximately omega(4) for small omega can be obtained both from general arguments and by detailed calculations for one-dimensional models.