Zobrazeno 1 - 10
of 191
pro vyhledávání: '"Gusmão, M."'
Publikováno v:
Phys. Rev. B 93 (2016) 205441
We study one-dimensional optical lattices described by generalized Aubry-Andr\'e models that include both commensurate and incommensurate modulations of the hopping amplitude. This brings together two interesting features of this class of systems: An
Externí odkaz:
http://arxiv.org/abs/1606.07100
Publikováno v:
Physical Review A 91 (2015) 033608
In this work we investigate the different states of a system of spin-1 bosons in two potential wells connected by tunneling, with spin-dependent interaction. The model utilizes the well-known Bose-Hubbard Hamiltonian, adding a local interaction term
Externí odkaz:
http://arxiv.org/abs/1502.07570
Publikováno v:
Phys. Rev. A 84, 055601 (2011)
We investigate the nature of the superfluid-insulator quantum phase transition driven by disorder for non-interacting ultracold atoms on one-dimensional lattices. We consider two different cases: Anderson-type disorder, with local energies randomly d
Externí odkaz:
http://arxiv.org/abs/1111.3666
Publikováno v:
Phys. Rev. A 82 (2010) 063634
We investigate the disorder-induced localization transition in Bose-Einstein condensates for the Anderson and Aubry-Andre models in the non-interacting limit using exact diagonalization. We show that, in addition to the standard superfluid fraction,
Externí odkaz:
http://arxiv.org/abs/1103.0577
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Akademický článek
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Autor:
Aligia, A. A., Gusmao, M. A.
We start from an effective Hamiltonian for Ru ions in a square lattice, which includes the on-site interactions between t_2g orbitals derived from Coulomb repulsion, and a tetragonal crystal-field splitting. Using perturbation theory in the hopping t
Externí odkaz:
http://arxiv.org/abs/cond-mat/0404506
Autor:
Gusmao, M. A., Ghivelder, L., Freitas, R. S., Ribeiro, R. A., de Lima, O. F., Damay, F., Cohen, L. F.
With the aim of probing the effect of magnetic disorder in the low-temperature excitations of manganites, specific-heat measurements were performed in zero field, and in magnetic fields up to 9 T in polycrystalline samples of La_{0.7-x}Y_{x}Ca_{0.3}M
Externí odkaz:
http://arxiv.org/abs/cond-mat/0306582
We present theoretical results for a Kondo-lattice model with spin-1/2 localized moments, including both the intrasite Kondo coupling and an intersite antiferromagnetic exchange interaction, treated within an extended mean-field approximation. We des
Externí odkaz:
http://arxiv.org/abs/cond-mat/0212034
Autor:
Ventura, C. I., Gusmao, M. A.
Tl2Mn2O7 exhibits important differences with other colossal magnetoresistance (CMR) compounds, like the Mn-perovskites, in its crystal structure and electronic properties, indicating the possibility of different mechanisms for CMR being present. The
Externí odkaz:
http://arxiv.org/abs/cond-mat/0106319