Related papers: Scalar Kinks
We study the low-temperature properties of S=1 and 1/2 alternating spin chains with antiferromagnetic nearest-neighbor exchange couplings using analytical techniques as well as a quantum Monte Carlo method. The spin-wave approach predicts…
We use neutron scattering to study the spin excitations associated with the stripe antiferromagnetic (AFM) order in semiconducting K$_{0.85}$Fe$_{1.54}$Se$_2$ ($T_N$=$280$ K). We show that the spin wave spectra can be accurately described…
We consider the effects of interactions on the nature of spinon excitations in Heisenberg spin-1/2 chains. We explicitly compute the two-spinon part of the longitudinal structure factor of the infinite chain in zero field for all values of…
We study the scattering behavior of scalar and spinor fields in the background of a gravitating cosmic string spacetime. The model explored here for the background vortex is non-abelian, becoming abelian in an appropriate limiting case. We…
Inelastic neutron scattering is used to investigate the collective magnetic excitations of the high-temperature superconductor parent antiferromagnet La2CuO4. We find that while the lower energy excitations are well described by spin-wave…
A variational approach for constructing an effective particle description of the low-energy physics of one-dimensional quantum spin chains is presented. Based on the matrix product state formalism, we compute the one- and two-particle…
Scattering of electrons from chiral spin textures such as the skyrmions is an emerging research area due to its richness in topological quantum transport, which is significant for spintronic devices. We study the dynamical process of…
A family of double-quantum excitation schemes is described for the solution nuclear magnetic resonance (NMR) of near-equivalent spin-1/2 pairs. These new methods exploit the spinor behaviour of 2-level systems, whose signature is the change…
The spin-S Heisenberg antiferromagnet on the two-dimensional lattice is investigated for S=1/2 and S=1. We consider interaction at isolated dimers ($J_{\rm d}$) and interaction bonds that form the bounce lattice ($J_{\rm b}$). For $J_{\rm…
We show that despite the absence of a Hopf term and zero Berry phase terms, the N`eel ordered phase of 2+1 D quantum antiferromagnets have spin 1/2 excitations, i.e. spinons. The spinons are skyrmion excitations of a topological nature.…
Many low dimensional spin systems with a dimerized or ladder-like antiferromagnetic exchange coupling have a gapped excitation spectrum with magnetic bound states within the spin gap. For spin ladders with an even number of legs the…
Charge kinks are considered as fundamental excitations in quarter-filled charge-ordered ladders. The strength of the coupling of the kinks to the three-dimensional lattice depends on their energy. The integrated intensity of Raman…
The $S=1/2$ kagome- and triangular-lattice Heisenberg antiferromagnets are investigated using the numerical exact diagonalization and the finite-size scaling analysis. The behaviour of the field derivative at zero magnetization is examined…
An S=1/2 anti-ferromagnetic spin chain is mapped to the two-flavor massless Schwinger model, which admits a gapless mode. In a spin ladder system rung interactions break the chiral invariance. These systems are solved by bosonization. If…
We present a (1+1)-dimensional fermionic QFT with non-local couplings between currents. This model describes an ensemble of spinless fermions interacting through forward, backward and umklapp scattering processes. We express the vacuum to…
We review unitarity and crossing constraints on scattering amplitudes for particles with spin in four dimensional quantum field theories. As an application we study two to two scattering of neutral spin 1/2 fermions in detail. Assuming…
In this work, we investigate the dynamics of a scalar field in the nonintegrable $\displaystyle \phi ^{4}$ model, restricted to the half-line. Here we consider singular solutions that interpolate the Dirichlet boundary condition…
Electron spin resonance experiments in the quasi-1D S=1/2 antiferromagnet K$_2$CuSO$_4$Cl$_2$ reveal opening of a gap in absence of magnetic ordering, as well as an anisotropic shift of the resonance magnetic field. These features of…
We investigate spin-flip excitations in the spin-1/2 trimer chain $\rm{Cu_3(P_2O_6OH)_2}$, featuring an antiferromagnetic exchange motif $J_1$-$J_1$-$J_2$ with $J_1 < J_2$. Using density matrix renormalization group (DMRG) simulations, we…
The resonant energy transfer mechanism, responsible for the presence of fractal patterns in the velocity diagrams of kink-antikink scattering, is analyzed for a family of two-component scalar field theory models, in which the kink solutions…