Matrix product state based algorithm for determining dispersion relations of quantum spin chains with periodic boundary conditionsReport as inadecuate




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(2012)PHYSICAL REVIEW B.85(3). Mark abstract We study a matrix product state algorithm to approximate excited states of translationally invariant quantum spin systems with periodic boundary conditions. By means of a momentum eigenstate ansatz generalizing the one of Ostlund and Rommer [see S. Ostlund and S. Rommer, Phys. Rev. Lett. 75, 3537 ( 1995); S. Rommer and S. Ostlund, Phys. Rev. B 55, 2164 (1997)], we separate the Hilbert space of the system into subspaces with different momentum. This gives rise to a direct sum of effective Hamiltonians, each one corresponding to a different momentum, and we determine their spectrum by solving a generalized eigenvalue equation. Surprisingly, many branches of the dispersion relation are approximated to a very good precision. We benchmark the accuracy of the algorithm by comparison with the exact solutions and previous numerical results for the quantum Ising, the antiferromagnetic Heisenberg spin-1/2, and the bilinear-biquadratic spin-1 models.

Please use this url to cite or link to this publication: http://hdl.handle.net/1854/LU-2119412



Author: B Pirvu, Jutho Haegeman and Frank Verstraete

Source: https://biblio.ugent.be/publication/2119412



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