B. A. Ivanov

MAGNON MODES AND MAGNON-VORTEX SCATTERING IN TWO-DIMENSIONAL EASY-PLANE FERROMAGNETS

We calculate the magnon modes in the presence of a vortex in a circular system, combining analytical calculations in the continuum limit with a numerical diagonalization of the discrete system. The magnon modes are expressed by the S-matrix for magnon-vortex scattering, as a function of the parameters and the size of the system and for different boundary conditions. Certain quasi-local translational modes are identified with the frequencies which appear in the trajectory X(t) of the vortex center in recent Molecular Dynamics simulations of the full many-spin model. Using these quasi-local modes we calculate the two parameters of a 3rd-order quation of motion for X(t). This equation was recently derived by a collective variable theory and describes very well the trajectories observed in the simulations. Both parameters, the vortex mass and a factor on the third time derivative of X(t), depend strongly on the boundary conditions.

Effective field theory for the S = 1 quantum nematic

For the

Dynamics and relaxation in spin nematics

S=1

Magnetic vortex as a ground state for micron-scale antiferromagnetic samples

system with general isotropic nearest-neighbor exchange, we derive the low-energy description of the spin nematic phase in terms of the

Excitation of coupled spin–orbit dynamics in cobalt oxide by femtosecond laser pulses

{\mathrm{RP}}^{2}

Chirality tunneling in mesoscopic antiferromagnetic domain walls

nonlinear

Amplitudes for magnon scattering by vortices in two-dimensional weakly easy-plane ferromagnets

\ensuremath{\sigma}

Semiclassical dynamics of domain walls in the one-dimensional Ising ferromagnet in a transverse field

model. In one dimension, quantum fluctuations destroy long-range nematic (quadrupolar) ordering, leading to the formation of a gapped spin liquid state being an analog of the Haldane phase for a spin nematic. Nematic analog of the Belavin-Polyakov instanton with

Dynamics of antiferromagnets exposed to ultrashort magnetic field pulses

{\ensuremath{\pi}}_{2}

Spin structure of antiferromagnetic disclination

topological charge 1/2 is constructed. In two dimensions the long-range order is destroyed by thermal fluctuations and at finite temperature the system is in a renormalized classical regime. Behavior in external magnetic field is discussed.