Quantum critical dynamics of the random transverse-field Ising spin chain

¹ HLRZ, Forschungszentrum Jülich - 52425 Jülich, Germany
² Research Institute for Solid State Physics - H-1525 Budapest, P.O.Box 49, Hungary, Institut für Theoretische Physik, Universität zu Köln - 50937 Köln, Germany

Received: 22 April 1997
Accepted: 10 June 1997

Abstract

Dynamical correlations of the spin and the energy density are investigated in the critical region of the random transverse-field Ising chain by numerically exact calculations in large finite systems . The spin-spin autocorrelation function is found to decay proportionally to and in the bulk and on the surface, respectively, with x_m and the bulk and surface magnetization exponents, respectively. On the other hand, the critical energy-energy autocorrelation functions have a power law decay, which are characterized by novel critical exponents in the bulk and at the surface, respectively. The numerical results are compared with the predictions of a scaling theory.