Related papers: Scalar Kinks
The ground state of the S=1/2 Heisenberg antiferomagnet on kagome can be viewed as a collection of fermionic spinons bound into small, heavy singlet pairs. Low-energy magnetic excitations in this system correspond to breaking the pairs into…
We use the variational matrix-product ansatz to study elementary excitations in the S=1/2 ladder with additional diagonal coupling, equivalent to a single S=1/2 chain with alternating exchange and next-nearest neighbor interaction. In…
We present a computational scheme to study spin excitations in magnetic materials from first principles. The central quantity is the transverse spin susceptibility, from which the complete excitation spectrum, including single-particle…
The square-lattice quantum Heisenberg antiferromagnet displays a pronounced anomaly of unknown origin in its magnetic excitation spectrum. The anomaly manifests itself only for short wavelength excitations propagating along the direction…
Treating Coulomb scattering of two free electrons in a stationary approach, we explore the momentum and spin entanglement created by the interaction. We show that a particular discretisation provides an estimate of the von Neumann entropy…
By a semi-analytical Bethe ansatz method and a T-matrix approach we study the scattering of a spinon, the elementary quantum many-body topological excitation in the 1D Heisenberg model, by local and phonon potentials. In particular, we…
Magnetically frustrated spin systems compose a significant proportion of topological quantum spin liquid candidates. Evidence for spin liquids in these materials comes largely from the detection of fractionalised spin-1/2 quasiparticles,…
We clarify elementary excitations in the $\Delta$-chain. They are found to be `kink'-`antikink' type domain wall excitations to the dimer singlet ground state. The characters of a kink and an antikink are quite different in this system: a…
We investigate the magnetic properties of the Cu-O planes in stoichiometric Sr$_{n-1}$Cu$_{n+1}$O$_{2n}$ (n=3,5,7,...) which consist of CuO double chains periodically intergrown within the CuO$_2$ planes. The double chains break up the…
A spin and phonon excitations spectrum are studied using quantum Monte Carlo method in antiferromagnetic chain with spins $S=1/2$ coupled nonadiabaticity with acoustic phonons . It is found the critical coupling exists to open gap in the…
We measure by inelastic neutron scattering the spin excitation spectra as a function of applied magnetic field in the quantum spin-ladder material (C5H12N)2CuBr4. Discrete magnon modes at low fields in the quantum disordered phase and at…
Theories containing infinite number of higher spin fields require a particular definition of summation over spins consistent with their underlying symmetries. We consider a model of massless scalars interacting (via bilinear conserved…
In this paper we analyze the scattering process in a two-field model in $(1+1)$-dimensions, with the special property to have several topological solutions: i) one with higher rest mass, characterized by a nested defect (lump inside a…
A large (infinitely-dimensional) class of completely integrable (possibly non-autonomous) spin chains is discovered associated to an infinite-dimensional Lie Algebra of infinite rank. The complete set of integrals of motion is constructed…
Results are presented of detailed numerical calculations for the spin excitation spectra of a two-dimensional electron gas confined in a quantum well of finite width w, at magnetic fields corresponding to the fractional and integral…
We study excitations of solitary waves -- the kinks -- in scalar models with degree eight polynomial self-interaction in (1+1) dimensions. We perform numerical studies of scattering of two kinks with an exponential asymptotic off each other…
We discuss the problem of spin-orbit interaction in a 2D chaotic or diffusive quantum dot in the presence of exchange correlations. Spin-orbit scattering breaks spin rotation invariance, and in the crossover regime between different…
We study the spin stiffness of a one-dimensional quantum antiferromagnet in the whole range of system sizes $L$ and temperatures $T$. We show that for integer and half-odd integer spin case the stiffness differs fundamentally in its $L$ and…
Using an electron spin resonance spectrometer covering a wide range of frequency and magnetic field, we have measured the low energy excitations of the S=1/2 tetragonal antiferromagnets, Sr_{2}CuO_{2}Cl_{2} and Sr_{2}Cu_{3}O_{4}Cl_{2}. Our…
Using high-resolution resonant inelastic x-ray scattering (RIXS), we performed a momentum-resolved study of magnetic excitations in the model spin-1/2 2D antiferromagnetic insulator Sr_2CuCl_2O_2. We identify both a single-spin-wave feature…