Acta Physica Polonica A

Hidden Domain Walls as Elementary Excitations in the Spin-1 Valence-Bond-Solid Model

Gábor Fáth, Jenő Sólyom

Published Feb 1, 1994• 1 citation

Abstract

Low-energy excitations are studied in the 1D S = 1 antiferromagnetic valence-bond-solid model.The lowest states are found to form a discrete triplet branch, separated from a higher-lying scattering continuum.The elementary excitations are argued to be "hidden" domain walls.

DOI: 10.12693/aphyspola.85.371

Related papers

Solitonic excitations in the Haldane phase of an S=1 chain

Gábor Fáth, Jenő Sólyom

We study low-lying excitations in the 1D S=1 antiferromagnetic valence-bond-solid (VBS) model. In a numerical calculation on finite systems the lowest excitations are found to form a discrete triplet branch, separated from the higher-lying continuum. The dispersion of these triplet excitations can be satisfactorily reproduced by assuming approximate wavefunctions. These wavefunctions are shown to correspond to moving hidden domain walls, i.e. to one-soliton excitations.

arXiv:cond-mat/9309011Journal of Physics Condensed MatterNov 29, 199343 citations

Spin triplet excitations for a valence bond solid on the kagome lattice

Bohm‐Jung Yang, Yong Baek Kim, Jaejun Yu +1 more

One of the most promising candidate ground states for the quantum antiferromagnetic Heisenberg model on the kagome lattice is the valence bond solid (VBS) with a 36-site unit cell. We present a theory of triplet excitation spectra about this ground state using bond operator formalism. In particular we obtain dispersions of all 18 triplet modes in the reduced Brillouin zone. In the bond operator mean-field theory, it is found that a large number of triplet modes are nondispersive. In particular, the lowest triplet excitation is nondispersive and degenerate with a dispersive mode at the zone center. Away from the zone center, the lowest triplet is separated from two other flat modes by a small energy gap. Quantum fluctuations are considered by taking into account scattering processes of two triplets and their bound-state formation, which leads to a downward renormalization of the lowest spin triplet gap. The dispersion of the lowest triplet excitation in the VBS state is compared with the dispersive lower bound of the triplet continuum expected in competing spin liquid phases. Implications to future neutron-scattering experiments are discussed.

arXiv:0802.4343Physical Review BJun 16, 200823 citations

Impurity-Bond Effect on the Spin-1 Antiferromagnetic Heisenberg Chain

Makoto Kaburagi, Isao Hrada, Takashi Tonegawa

Low-lying excited states of the spin-1 antiferromagnetic Heisenberg chain with an impurity bond are investigated in terms of domain-wall excitations by means of analytical methods as well as a method of numerical diagonalization.It is shown that 1) the impurity bond brings about a massive triplet mode in the Haldane gap, 2) the triplet state comprises three of the four ground states of an open chain, 3) the excited states with the domain wall trapped at the impurity bond, including the massive triplet mode, exhibit a Néel-type configuration of the magnetic moment around the impurity bond.On the basis of the present results, we propose a new energy versus magnetic-field diagram.

Journal of the Physical Society of JapanJan 15, 19940 citations

Impurity-Bond Effect on the Spin-1 Antiferromagnetic Heisenberg Chain

Makoto Kaburagi, Isao Harada, Takashi Tonegawa

Low-lying excited states of the spin-1 antiferromagnetic Heisenberg chain with an impurity bond are investigated in terms of domain-wall excitations by means of analytical methods as well as a method of numerical diagonalization. It is shown that 1) the impurity bond brings about a massive triplet mode in the Haldane gap, 2) the triplet state comprises three of the four ground states of an open chain, 3) the excited states with the domain wall trapped at the impurity bond, including the massive triplet mode, exhibit a Néel-type configuration of the magnetic moment around the impurity bond. On the basis of the present results, we propose a new energy versus magnetic-field diagram.

arXiv:cond-mat/9304040Journal of the Physical Society of JapanJun 15, 199328 citations

Hidden symmetry breaking in a generalized valence-bond solid model

Kiyohito Totsuka, Masuo Suzuki

A 'boson' representation for the ground state of the generalized valence-bond solid model is derived. The relation between this expression and the matrix-product representation of Klumper et al. (1991,1992) is discussed. It is shown that the hidden Z 2 *Z 2 -symmetry is partially broken in this model. Elementary excitations of this system have a topological nature similar to that in the Affleck, Kennedy, Lieb and Tasaki (1988) model.

Journal of Physics A Mathematical and GeneralOct 7, 199420 citations

Nature of Spinons in 1D Spin Chains

Teresa Kulka, Miłosz Panfil, Mona Berciu +1 more

We provide an intuitive understanding of the collective low-energy spin excitation of the one-dimensional spin-1/2 antiferromagnetic Heisenberg chain, known as the spinon. To this end, we demonstrate how a single spinon can be excited by adding one extra spin to the ground state. This procedure accurately reproduces all key features of the spinon's dispersion. These follow from the vanishing norm of the excited state which is triggered by the ground state entanglement. Next, we show that the spinon dispersion can be approximately reproduced if we replace the true ground state with the simplest valence-bond solid. This proves that the spinon of the one-dimensional Heisenberg model can be understood as a single spin flowing through a valence-bond solid.

arXiv:2303.02276Physical Review LettersMay 29, 20256 citations