Related papers: Finite Temperature Dynamical Structure Factor of t…
We investigate the classical antiferromagnetic Heisenberg model on the triangular lattice with up to third-nearest neighbor exchange couplings using the Nematic Bond Theory. This approach allows us to compute the free energy and the neutron…
The infinite Heisenberg XXZ spin-(1/2) chain in the gapped antiferromagnetic regime has two degenerate vacua and kink topological excitations (which are also called spinons) interpolating between these vacua as elementary excitations.…
The Heisenberg XXZ spin-1/2 chain is considered in the massive antiferromagnetic regime in the presence of a staggered longitudinal magnetic field. The Hamiltonian of the model is characterised by the anisotropy parameter $\Delta<-1$, and…
Inelastic neutron scattering is employed to study transverse spin correlations of a Heisenberg $S=1/2$ chain compound in a magnetic field of 7.5 T. The target compound is the antiferromagnetic Heisenberg $S=1/2$ chain material…
We present a study of the spin-1/2 Heisenberg chain with alternating ferro- and antiferromagnetic exchange, focusing on the role of the exchange couplings to cover both, dimer and Haldane limit. Employing a complementary combination of…
The concept of negativity is adapted in order to explore the quantum and thermal entanglement of the mixed spin-(1/2,$S$) Heisenberg dimers in presence of an external magnetic field. The mutual interplay between the spin size $S$, XXZ…
Static and dynamic structure factors of Heisenberg ferrimagnetic spin chains are numerically investigated. There exist two distinct branches of elementary excitations, which exhibit ferromagnetic and antiferromagnetic aspects. The…
Dynamical structure factors of the S=1 bond-alternating spin chains in the dimer phase are calculated at finite temperature, using the pair dynamical correlated-effective-field approximation. At T=0, the delta-function-type peak of the…
We investigate the asymptotic behaviour of spin-spin correlation functions for the integrable Heisenberg chain. To this end we use the Quantum Transfer Matrix (QTM) technique developed in \cite{AK} which results in a set of non-linear…
The spin-1/2 XXZ Heisenberg magnet is considered for the case of the anisotropy parameter tending to infinity (so-called, Ising limit). A thermal correlation function of the ferromagnetic string is calculated over the ground state. The…
The magnetic and thermodynamic properties of spin-1/2 Heisenberg diamond chains are investigated in three different cases: (a) J1, J2, J3>0 (frustrated); (b) J1, J3<0, J2>0 (frustrated); and (c) J1, J2>0, J3<0 (non-frustrated). The density…
We present a spin-rotation-invariant Green-function theory for the dynamic spin susceptibility in the spin-1/2 antiferromagnetic Heisenberg model on a stacked honeycomb lattice. Employing a generalized mean-field approximation for arbitrary…
We investigate transport in several translationally invariant spin-1/2 chains in the limit of high temperatures. We concretely consider spin transport in the anisotropic Heisenberg chain, the pure Heisenberg chain within an alternating…
We develop a finite-temperature perturbation theory for quasi-one-dimensional quantum spin systems, in the manner suggested by H.J. Schulz (1996) and use this formalism to study their dynamical response. The corrections to the random-phase…
We study finite temperature properties of a generic spin-orbital model relevant to transition metal compounds, having coupled quantum Heisenberg-spin and Ising-orbital degrees of freedom. The model system undergoes a phase transition,…
Motivated by a novel bimetallic chain compound in which alternating magnetic centers are ferromagnetically coupled, we investigate thermodynamic properties of one-dimensional spin-$(S,s)$ Heisenberg ferromagnets both numerically and…
A spectrum exhibiting $E_8$ symmetry is expected to arise when a small longitudinal field is introduced in the transverse-field Ising chain at its quantum critical point. Evidence for this spectrum has recently come from neutron scattering…
The stranglehold of low temperatures on fascinating quantum phenomena in one-dimensional quantum magnets has been challenged recently by the discovery of anomalous spin transport at high temperatures. Whereas both regimes have been…
We consider the problem of computing form factors of the massless XXZ Heisenberg spin-1/2 chain in a magnetic field in the (thermodynamic) limit where the size M of the chain becomes large. For that purpose, we take the particular example…
The bipartite quantum and thermal entanglement is quantified within pure and mixed states of a mixed spin-(1/2,1) Heisenberg dimer with the help of negativity. It is shown that the negativity, which may serve as a measure of the bipartite…