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...

Full description

Bibliographic Details
Main Authors: Gurarie, V, Chalker, J
Format: Journal article
Language:English
Published: 2002
Description
Summary: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.