Zobrazeno 1 - 10
of 456
pro vyhledávání: '"Grimm, U."'
Publikováno v:
Philosophical Magazine 86 (2006) 733-739
The stable magnetisation configurations of antiferromagnets on quasiperiodic tilings are investigated theoretically. The exchange coupling is assumed to decrease exponentially with the distance between magnetic moments. It is demonstrated that the co
Externí odkaz:
http://arxiv.org/abs/cond-mat/0509461
We report results of numerical simulations of wave-packet dynamics in a class of chains consisting of two types of weakly coupled clusters arranged in a quasiperiodic sequence. Properties of eigenstates are investigated using perturbation theory of d
Externí odkaz:
http://arxiv.org/abs/cond-mat/0412618
Publikováno v:
Phys. Rev. B 72, 054203 (2005)
Spectral properties and anomalous diffusion in the silver-mean (octonacci) quasicrystals in d=1,2,3 are investigated using numerical simulations of the return probability C(t) and the width of the wave packet w(t) for various values of the hopping st
Externí odkaz:
http://arxiv.org/abs/cond-mat/0407762
Publikováno v:
Phys. Rev. Lett. 93, 076407 (2004)
Based on Monte-Carlo simulations, the stable magnetization configurations of an antiferromagnet on a quasiperiodic tiling are derived theoretically. The exchange coupling is assumed to decrease exponentially with the distance between magnetic moments
Externí odkaz:
http://arxiv.org/abs/cond-mat/0406373
Publikováno v:
Nucl. Phys. B 618(3)FS (2001) 650-674.
A strongly correlated electron system associated with the quantum superalgebra ${U}_q[{osp}(2|2)]$ is studied in the framework of the quantum inverse scattering method. By solving the graded reflection equation, two classes of boundary-reflection $K$
Externí odkaz:
http://arxiv.org/abs/cond-mat/0106511
Publikováno v:
J. Phys. A: Math. Gen. 33 (2000) 3863-3879
Employing the graded versions of the Yang-Baxter equation and the reflection equations, we construct two kinds of integrable impurities for a small-polaron model with general open boundary conditions: (a) we shift the spectral parameter of the local
Externí odkaz:
http://arxiv.org/abs/nlin/0001040
Publikováno v:
Int. J. Mod. Phys. B 8 (1994) 3579-3600
A zero-field Ising model with ferromagnetic coupling constants on the so-called Labyrinth tiling is investigated. Alternatively, this can be regarded as an Ising model on a square lattice with a quasi-periodic distribution of up to eight different co
Externí odkaz:
http://arxiv.org/abs/solv-int/9902009
Autor:
Hermisson, J., Grimm, U.
Publikováno v:
Phys. Rev. B57, 673 (1998) (Rapid Communication)
We consider Ising quantum chains with quenched aperiodic disorder of the coupling constants given through general substitution rules. The critical scaling behaviour of several bulk and surface quantities is obtained by exact real space renormalizatio
Externí odkaz:
http://arxiv.org/abs/cond-mat/9711096
Publikováno v:
Phys. Rev. Lett. 80, 3996 (1998)
We study the statistical properties of energy spectra of two-dimensional quasiperiodic tight-binding models. We demonstrate that the nearest-neighbor level spacing distributions of these non-random systems are well described by random matrix theory.
Externí odkaz:
http://arxiv.org/abs/cond-mat/9710006
Publikováno v:
J. Stat. Phys. 78 (1995) 285
The study of zeros of partition functions, initiated by Yang and Lee, provides an important qualitative and quantitative tool in the study of critical phenomena. This has frequently been used for periodic as well as hierarchical lattices. Here, we co
Externí odkaz:
http://arxiv.org/abs/cond-mat/9311017