arXiv subjects

P. Hasenfratz

Publications and source records attributed to P. Hasenfratz.

20 records · Page 2Linked to original sources

arXiv1993

Perfect lattice action for asymptotically free theories

There exist lattice actions which give cut--off independent physical predictions even on coarse grained lattices. Rotation symmetry is restored, the spectrum becomes exact and, in addition, the classical equations have scale invariant instanton solutions. This perfect action can be made short ranged. It can be determined by combining analytical calculations with numerical simulations on small lattices. We illustrate the method and the benefits on the $d=2$ non--linear $σ$--model.

hep-lat↗

arXiv1992

Finite size and temperature effects in the AF Heisenberg model

The low temperature and large volume effects in the d=2+1 antiferromagnetic quantum Heisenberg model are dominated by magnon excitations. The leading and next-to-leading corrections are fully controlled by three physical constants, the spin stiffness, the spin wave velocity and the staggered magnetization. Among others, the free energy, the ground state energy, the low lying excitations, staggered magnetization, staggered and uniform susceptibilities are studied here. The special limits of very low temperature and infinite volume are considered also.

hep-lat↗