Related papers: Spectral Function for the S=1 Heisenberg Antiferro…
In the paper we describe the modification of spin-wave theory for one-dimensional isotropic antiferromagnet. This theory enables to obtain the energy of magnetic excitations of short wave length and correlation function in agreement with…
We give the details of the calculation of the spectral functions of the 1D Hubbard model using the spin-charge factorized wave-function for several versions of the U -> +\infty limit. The spectral functions are expressed as a convolution of…
Using the density matrix renormalization group technique, we calculate numerically the low energy excitation spectrum and magnetization curve of the spin-1 antiferromagnetic chain in a staggered magnetic field, which is expected to describe…
We show some symmetry relations among the correlation functions of the integrable higher-spin XXX and XXZ spin chains, where we explicitly evaluate the multiple integrals representing the one-point functions in the spin-1 case. We review…
We present results for in-medium spectral functions obtained within the Functional Renormalization Group framework. The analytic continuation from imaginary to real time is performed in a well-defined way on the level of the flow equations.…
We investigate the application of a perturbative renormalization group (RG) method to random antiferromagnetic Heisenberg chains with arbitrary spin size. At zero temperature we observe that initial arbitrary probability distributions…
We study a system of one-dimensional (iso)spin-1/2 bosons in the regime of strong repulsive interactions. We argue that the low-energy spectrum of the system consists of acoustic density waves and the spin excitations described by an…
We first review the method to calculate the spectral functions in the functional renormalization group (FRG) approach, which has been recently developed. We also provide the numerical stability conditions given by the present authors for a…
The impact of the non-2-spinon excitations of the one-dimensional $S=1/2$ Heisenberg antiferromagnet on the integrated intensity, the susceptibility, the frequency moments, and the Euclidian time representation of the $T=0$ dynamic spin…
Inelastic neutron-scattering and finite-temperature density matrix renormalization group (DMRG) calculations are used to investigate the spin excitation spectrum of the $S=1/2$ Heisenberg spin chain compound K$_2$CuSO$_4$Cl$_2$ at several…
We have mapped from the quantum to the classical limit the spin excitation spectrum of the antiferromagnetic spin-1 Heisenberg chain system CsNiCl3 in its paramagnetic phase from T=5 to 200K. Neutron scattering shows that the excitations…
We use numerical and analytical results to construct a simple ansatz for the energy dynamical correlation function of the 1D antiferromagnetic Heisenberg model. This is applied to compute the phonon assisted absorption spectra of magnetic…
The spectral properties of itinerant 2D systems with (nearly) ferromagnetic ground state are studied within the spin-fermion and the classical s-d exchange models. While the former model describes the effect of collective magnetic…
The exact expression derived by Bougourzi, Couture, and Kacir for the 2-spinon contribution to the dynamic spin structure factor $S_{zz}(q,\omega)$ of he one-dimensional $S$=1/2 Heisenberg antiferromagnet at $T=0$ is evaluated for direct…
We investigate an antiferromagnetic spin-$1$ Heisenberg chain in the presence of Dyzaloshinskii-Moriya interactions (DMI) and an external magnetic field. We study the resulting spin chain using a combination of numerical and analytical…
We leverage random phase approximation and unbiased auxiliary-field quantum Monte Carlo methods to compute dynamical correlations for a dilute homogeneous two-dimensional attractive Fermi gas. Our main purpose is to quantitatively study the…
The density-matrix renormalization-group technique is used to calculate the spin correlation functions <S^x_jS^x_k> and <S^z_jS^z_k> of the one-dimensional S=1/2 XXZ model in the gapless regime. The numerical results for open chains of 200…
Inelastic neutron scattering is used to identify single-particle and continuum spin excitations in the quasi-one-dimensional $S=1/2$ antiferromagnet \ba. In the data analysis, close attention is given to resolution effects. A gap in the…
We study theoretically the Raman scattering spectra in the one-dimensional (1D) quantum spin-1/2 antiferromagnets. The analysis reveals that their low-energy dynamics is exquisitely sensitive to various perturbations to the Heisenberg chain…
We study the 1-dimensional Heisenberg antiferromagnet with s=1/2 using a Majorana representation of the s=1/2 spins. A simple Hartree-Fock approximation of the resulting model gives a bilinear fermionic description of the model. This…