title: Long-range quantum Ising spin glasses at t=0: gapless collective excitations and universality.
abstract: We solve the Sherrington-Kirkpatrick model in a transverse field Γ deep in its quantum glass phase at zero temperature. We show that the glass phase is critical everywhere, exhibiting collective excitations with a gapless Ohmic spectral function. Using an effective potential approach, we interpret the latter as arising from disordered collective excitations behaving like weakly coupled, underdamped oscillators. For a small transverse field Γ, the low-frequency spectrum takes a form independent of the fluctuation strength Γ.
authors.affiliation: The Abdus Salam ICTP-Strada Costiera 11, 34151, Trieste, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Andreanov
authors.forename: M
authors.initials: M
authors.lastname: Müller