Related papers: Optical observation of quasiperiodic Heisenberg an…
The scattering matrix of the Schrodinger operator with smooth short-range electric and magnetic potentials is considered. The asymptotic density of the eigenvalues of this scattering matrix in the high energy regime is determined. An…
We study an extended spin-$1/2$ antiferromagnetic Heisenberg model on the triangular lattice, which includes both nearest- and next-nearest-neighbor interactions, as well as a scalar chiral term. This model exhibits a rich phase diagram…
Nuclear spin-lattice relaxation in one-dimensional Heisenberg ferrimagnets is studied by means of a modified spin-wave theory. We consider the second-order process, where a nuclear spin flip induces virtual spin waves which are then…
A major focus of experimental interest in Sr2IrO4 has been to clarify how the magnetic excitations of this strongly spin-orbit coupled system differ from the predictions of anisotropic 2D spin-1/2 Heisenberg model and to explore the extent…
The class of Ruddlesden-Popper type (PEA)$_2$PbI$_4$ perovskites comprises two-dimensional (2D) structures whose optical properties are determined by excitons with a large binding energy of about 260 meV. It complements the family of other…
The coupling between spin and charge degrees of freedom in a crystal imparts strong optical signatures on scattered electromagnetic waves. This has led to magneto-optical effects with a host of applications, from the sensitive detection of…
NiGa$_2$S$_4$ is a triangular lattice S=1 system with strong two-dimensionality of the lattice, actively discussed as a candidate to host spin-nematic order brought about by strong quadrupole coupling. Using Raman scattering spectroscopy we…
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…
A Green-function theory for the dynamic spin susceptibility in the square-lattice spin-1/2 antiferromagnetic compass-Heisenberg model employing a generalized mean-field approximation is presented. The theory describes magnetic long-range…
Dynamical correlations of Jeff = 1/2 isospins in the paramagnetic state of spin-orbital Mott insu- lator Sr2IrO4 was revealed by resonant magnetic x-ray diffuse scattering. We found two-dimensional antiferromagnetic fluctuation with a large…
We present theoretical results concerning inelastic light (Raman) scattering from semiconductor quantum dots. The characteristics of each dot state (whether it is a collective or single-particle excitation, its multipolarity, and its spin)…
Perfect deporalization of the Loudon-Fleury inelastic visible-light scattering in the Kitaev honeycomb model is well known. Though it happens in Heisenberg Kagome and triangular antiferromagnets as well, yet we prove it to be of geometric…
Multipolar order, such as octupolar order, is a key concept in condensed matter physics, particularly in light of elusive hidden orders. However, its experimental identification remains challenging due to the absence of direct coupling to…
Anelastic light scattering is computed numerically for model disordered systems (linear chains and 2-dimensional site and bond percolators), with and without electrical disorder. A detailed analysis of the vibrational modes and of their…
We study how well magnetic models can be implemented with ultracold bosonic atoms of two different hyperfine states in an optical superlattice. The system is captured by a two-species Bose-Hubbard model, but realizes in a certain parameter…
Optical magnetometers use the rotation of linearly polarized laser light induced by the Faraday effect for high precision magnetic field measurements. Here, we carry out an in-depth quantum information investigation, deploying two distinct…
We investigate magnetic excitations in an $S=3/2$ Heisenberg model representing two-dimensional antiferromagnet ${\rm Ba_2CoGe_2O_7}$. In terahertz absorption experiment of the compound, Goldstone mode as well as novel magnetic excitations,…
Magnetic excitations in layered magnetic materials that can be thinned down the two-dimensional (2D) monolayer limit are of high interest from a fundamental point of view and for applications perspectives. Raman scattering has played a…
Based on a two-band model, we study the electronic Raman scattering intensity in both normal and superconducting states of iron-pnictide superconductors. For the normal state, due to the match or mismatch of the symmetries between band…
We extend a microscopic theory of polarization and magnetization to include the spin degree of freedom of the electrons, introducing a general spin orbit coupling and Zeeman interaction term in the Hamiltonian. At finite frequencies and…