Low-frequency internal friction in silica glass F. Travasso, P. Amico, L. Bosi, F. Cottone, A. Dari, L. Gammaitoni, H. Vocca and F. Marchesoni EPL, 80 5 (2007) 50008 Published online: 31 October 2007 DOI: 10.1209/0295-5075/80/50008