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pro vyhledávání: '"Bilstein, Ulrich"'
Autor:
Bilstein, Ulrich
We calculate the magnetization profiles of the $\sigma_j^x$ and $\sigma_j^z$ operators for the XX-model with hermitian boundary terms. We study the profiles on the finite chain and in the continuum limit. The results are discussed in the context of c
Externí odkaz:
http://arxiv.org/abs/cond-mat/0004484
Autor:
Bilstein, Ulrich, Rittenberg, Vladimir
It is shown that an operator (in general non-local) commutes with the Hamiltonian describing the finite XX quantum chain with certain non-diagonal boundary terms. In the infinite volume limit this operator gives the "topological" charge.
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Externí odkaz:
http://arxiv.org/abs/cond-mat/0004241
Autor:
Bilstein, Ulrich
We compute the continuum limit of the spectra for the XX-model with arbitrary complex boundary fields. In the case of hermitian boundary terms one obtains the partition functions of the free compactified boson field on a cylinder with Neumann-Neumann
Externí odkaz:
http://arxiv.org/abs/cond-mat/0002162
Autor:
Bilstein, Ulrich, Wehefritz, Birgit
Publikováno v:
J. Phys. A 32 (1999) 191-233
This is the first of three papers dealing with the XX finite quantum chain with arbitrary, not necessarily hermitian, boundary terms. This extends previous work where the periodic or diagonal boundary terms were considered. In order to find the spect
Externí odkaz:
http://arxiv.org/abs/cond-mat/9807166
Autor:
Bilstein, Ulrich, Wehefritz, Birgit
Publikováno v:
J. Phys. A 30 (1997) 4925
The spectrum of the non-hermitian asymmetric XXZ-chain with additional non-diagonal boundary terms is studied. The lowest lying eigenvalues are determined numerically. For the ferromagnetic and completely asymmetric chain that corresponds to a reacti
Externí odkaz:
http://arxiv.org/abs/cond-mat/9611163
Autor:
Bilstein, Ulrich, Rittenberg, Vladimir
Publikováno v:
Journal of Physics: A Mathematical & General; 10/27/2000, Vol. 33 Issue 42, pL381-L385, 5p
Autor:
Bilstein, Ulrich
Publikováno v:
Journal of Physics: A Mathematical & General; 11/3/2000, Vol. 33 Issue 43, p1-1, 1p
Autor:
Bilstein, Ulrich
Publikováno v:
Journal of Physics: A Mathematical & General; 6/23/2000, Vol. 33 Issue 24, p1-1, 1p
Autor:
Bilstein, Ulrich, Wehefritz, Birgit
Publikováno v:
Journal of Physics: A Mathematical & General; 1/15/1999, Vol. 32 Issue 2, p1-1, 1p
Autor:
Bilstein, Ulrich, Wehefritz, Birgit
Publikováno v:
Journal of Physics: A Mathematical & General; 7/21/1997, Vol. 30 Issue 14, p1-1, 1p