Application of a continuous time cluster algorithm to the two-dimensional random quantum Ising ferromagnet
NIC, c/o Forschungszentrum Jülich, 52425 Jülich, Germany
2 Department of Physics, Toho University, Miyama 2-2-1, Funabashi 274, Japan
Published online: 15 May 1999
A cluster algorithm formulated in continuous (imaginary) time is presented for Ising models in a transverse field. It works directly with an infinite number of time-slices in the imaginary time direction, avoiding the necessity to take this limit explicitly. The algorithm is tested at the zero-temperature critical point of the pure two-dimensional (2d) transverse Ising model. Then it is applied to the 2d Ising ferromagnet with random bonds and transverse fields, for which the phase diagram is determined. Finite size scaling at the quantum critical point as well as the study of the quantum Griffiths-McCoy phase indicate that the dynamical critical exponent is infinite as in 1d.
PACS: 75.50.Lk – Spin glasses and other random magnets / 05.30.-d – Quantum statistical mechanics / 75.10.Nr – Spin-glass and other random models
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999