arXiv subjects

W. Hofstetter

Publications and source records attributed to W. Hofstetter.

39 records · Page 3Linked to original sources

arXiv1998

Low temperature thermodynamics of inverse square spin models in one dimension

We present a field-theoretic renormalization group calculation in two loop order for classical O(N)-models with an inverse square interaction in the vicinity of their lower critical dimensionality one. The magnetic susceptibility at low temperatures is shown to diverge like $T^{-a} \exp(b/T)$ with $a=(N-2)/(N-1)$ and $b=2π^2/(N-1)$. From a comparison with the exactly solvable Haldane-Shastry model we find that the same temperature dependence applies also to ferromagnetic quantum spin chains.

cond-mat.stat-mech↗

arXiv1998

Frustration of antiferromagnetism in the t-t'-Hubbard model at weak coupling

The perfect-nesting instability towards antiferromagnetism of the Hubbard model is suppressed by next-nearest neighbor hopping t'. The exact asymptotic behavior of the critical coupling U_c(t') at small t' is calculated in dimensions d=2,3 and infinity using Hartree theory, and the order of the transition is determined. A region of stability of a metallic antiferromagnetic phase in d=3 is identified.

cond-mat.str-el↗

arXiv1996

The Single-Electron-Box and the Helicity Modulus of an inverse square XY-Model

We calculate the average number of electrons on a metallic single-electron-box as a function of the gate voltage for arbitrary values of the tunneling conductance. In the vicinity of the plateaus the problem is equivalent to calculating the helicity modulus of a classical inverse square XY-model in one dimension. By a combination of perturbation theory, a two-loop renormalization group calculation and a Monte-Carlo simulation in the intermediate regime we provide a complete description of the smearing of the Coulomb staircase at zero temperature with increasing conductance.

cond-mat.mes-hall↗