Related papers: Effective field theory for S=1 quantum nematic
The low-energy effective Hamiltonian of three coupled spin chains with periodic boundary conditions (spin tube) is expressed, in the limit of strong interchain coupling, in terms of XXZ chains coupled by biquadratic exchange interaction. A…
We study the properties of spin systems realized by cold polar molecules interacting via dipole-dipole interactions in two dimensions. Using a spin wave theory, that allows for the full treatment of the characteristic long-distance tail of…
A lattice system of spinor atoms or molecules experiencing quadratic Zeeman effect is considered. This can be an optical lattice with sufficiently deep wells at lattice sites, so that the system is in an isolating state, where atoms are…
We study theoretically the far-from-equilibrium relaxation dynamics of spin spiral states in the three dimensional isotropic Heisenberg model. The investigated problem serves as an archetype for understanding quantum dynamics of isolated…
We study the effects of quantum fluctuations in magnetic properties of quantum frustrated ferromagnets in a magnetic field. It is shown that a non-classical phase or a phase separation appears due to quantum fluctuations below the…
We propose a formalism to take account of the correction of the spatial fluctuations to the local self-energy obtained by the dynamical mean-field approximation. For this purpose, the approximate dynamical susceptibility in the framework of…
There are constructed exact solutions of the quantum-mechanical equation for a spin S=1 particle in 2-dimensional Riemannian space of constant positive curvature, spherical plane, in presence of an external magnetic field, analogue of the…
We propose a semiclassical framework for solving open quantum dynamics in driven-dissipative spin systems. Our method consists of generalized spin-wave approximations tailored to describing quantum trajectories unravelled from the master…
The interplay between quantum Hall ordering and spontaneously broken "internal" symmetries in two-dimensional electron systems with spin or pseudospin degrees of freedom gives rise to a variety of interesting phenomena, including novel…
We construct a low-energy effective field theory that permits the complete treatment of isospin-breaking effects in nonleptonic weak interactions to next-to-leading order. To this end, we enlarge the chiral Lagrangian describing strong and…
We consider properties of a two-dimensional electron system in a random magnetic field. It is assumed that the magnetic field not only influences orbital electron motion but also acts on the electron spin. For calculations, we suggest a new…
The $S=1/2$ XXZ spin chain with the staggered XY anisotropy $$ H = J \sum_{n}^{N} (S^{x}_{n} S^{x}_{n+1} + S^{y}_{n} S^{y}_{n+1} + \Delta S^{z}_{n} S^{z}_{n+1}) - \delta \sum_{n}^{N} (-1)^{n} (S^{x}_{n} S^{x}_{n+1} - S^{y}_{n} S^{y}_{n+1})…
The $|\Delta S|=1$ $\Lambda N$ interaction, responsible for the decay of hypernuclei, is studied by means of an Effective Field Theory where the long range physics is described by pion and kaon exchange mechanisms, and its short range…
A partial resummation of perturbation theory is described for field theories containing spin-1/2 particles in states that may be far from thermal equilibrium. This allows the nonequilibrium state to be characterized in terms of…
We study a driven-dissipative model of spins one-half (qubits) on a lattice with nearest-neighbor interactions. Focusing on the role of spatially extended spin-spin correlations in determining the phases of the system, we characterize the…
Effect of quantum fluctuations concerned with the orbital degrees of freedom is discussed for the model with SU(4) symmetry in one dimension. An effective Hamiltonian is derived from the orbitally degenerate Hubbard model at quarter…
The phase transitions that occur in an infinite-range-interaction Ising ferromagnet in the presence of a double-Gaussian random magnetic field are analyzed. Such random fields are defined as a superposition of two Gaussian distributions,…
The simplest higher-spin interactions involve classical external currents and symmetric tensors $\phi_{\m_1 ... \m_s}$, and convey three instructive lessons. The first is a general form of the van Dam-Veltman-Zakharov discontinuity in flat…
The ground state properties of the S=1/2 transverse-field Ising model on the checkerboard lattice are studied using linear spin wave theory. We consider the general case of different couplings between nearest neighbors (J1) and…
The topological physics of quantum Hall states is efficiently encoded in purely topological quantum field theories of the Chern-Simons type. The reliable inclusion of low-energy dynamical properties in a continuum description however…