scholarly journals Magnetic Translation Symmetry on the Lattice

2009 ◽  
Vol 122 (2) ◽  
pp. 293-307
Author(s):  
K.-i. Sekiguchi ◽  
T. Okamoto ◽  
T. Fujiwara
Keyword(s):  
Translation Symmetry ◽  
Magnetic Translation

SPIN WAVE MODES AND MAGNON SCATTERING AT SURFACE NANOSTRUCTURE ON 2D HEISENBERG FERROMAGNETS

2004 ◽  
Vol 11 (01) ◽  
pp. 99-109 ◽  
Author(s):  
MEHAND BELHADI ◽  
ANTOINE KHATER
Keyword(s):  
Spin Wave ◽  
Spin Fluctuation ◽  
Mathematical Framework ◽  
Electronic Effects ◽  
Magnetic Nanostructure ◽  
Surface Nanostructure ◽  
Translation Symmetry ◽  
Scattering Spectra ◽  
Magnetic Translation ◽  
Wave Modes

We investigate the spin fluctuation dynamics and the scattering phenomena at adsorbed magnetic nanostructure on the surface of two-dimensional Heisenberg ferromagnets. The surface is considered as an infinite slab of two coupled atomic layers, and the nanostructure as an isolated monatomic chain on the surface of a cubic lattice. No electronic effects are considered but local changes in exchange fields between the localized spins of the nanostructure and the magnetically ordered substrate are assumed to be dominant. The mathematical framework of the matching method is used to analyze both the localization and the scattering phenomena at the nanostructure boundaries. The energy of spin wave localized modes arising from the absence of magnetic translation symmetry is determined. The transmission and reflection probabilities as well as the spin wave average transmittance across the nanostructure are calculated and numerical results are presented in a large range of scattering energies. It is shown that there are several localized spin wave modes associated with the nanostructure which may be either optical or acoustical modes (depending on the system parameters), and the coherent coupling between these localized spin modes and the propagating spin modes of the system leads to Fano resonances in the scattering spectra.

A METHOD OF DESCRIPTION OF MAGNETIC OSCILLATIONS IN MESOSCOPIC SYSTEMS

1996 ◽  
Vol 10 (27) ◽  
pp. 1333-1338
Author(s):  
STANISLAW WALCERZ
Keyword(s):  
Experimental Investigation ◽  
Magnetic Properties ◽  
Translation Group ◽  
Mesoscopic Systems ◽  
Group Approach ◽  
Proposed Model ◽  
Planar Systems ◽  
Magnetic Translation ◽  
Onsager Theory ◽  
Magnetic Oscillations

A model for calculation of magnetic properties of small planar systems is proposed. The model combines the Onsager theory of de Haas-van Alphen oscillations with the magnetic translation group approach. The proposed model suggests a method for both theoretical and experimental investigation of magnetic properties of mesoscale systems.

scholarly journals Quasi-Lie Brackets and the Breaking of Time-Translation Symmetry for Quantum Systems Embedded in Classical Baths

Symmetry ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 518 ◽  
Author(s):  
Alessandro Sergi ◽  
Gabriel Hanna ◽  
Roberto Grimaudo ◽  
Antonino Messina
Keyword(s):  
Constant Temperature ◽  
Degrees Of Freedom ◽  
Open Quantum Systems ◽  
Hamiltonian Dynamics ◽  
Quantum Systems ◽  
Classical Dynamics ◽  
Open Quantum ◽  
Time Translation ◽  
Translation Symmetry ◽  
Lie Brackets

Many open quantum systems encountered in both natural and synthetic situations are embedded in classical-like baths. Often, the bath degrees of freedom may be represented in terms of canonically conjugate coordinates, but in some cases they may require a non-canonical or non-Hamiltonian representation. Herein, we review an approach to the dynamics and statistical mechanics of quantum subsystems embedded in either non-canonical or non-Hamiltonian classical-like baths which is based on operator-valued quasi-probability functions. These functions typically evolve through the action of quasi-Lie brackets and their associated Quantum-Classical Liouville Equations, or through quasi-Lie brackets augmented by dissipative terms. Quasi-Lie brackets possess the unique feature that, while conserving the energy (which the Noether theorem links to time-translation symmetry), they violate the time-translation symmetry of their algebra. This fact can be heuristically understood in terms of the dynamics of the open quantum subsystem. We then describe an example in which a quantum subsystem is embedded in a bath of classical spins, which are described by non-canonical coordinates. In this case, it has been shown that an off-diagonal open-bath geometric phase enters into the propagation of the quantum-classical dynamics. Next, we discuss how non-Hamiltonian dynamics may be employed to generate the constant-temperature evolution of phase space degrees of freedom coupled to the quantum subsystem. Constant-temperature dynamics may be generated by either a classical Langevin stochastic process or a Nosé–Hoover deterministic thermostat. These two approaches are not equivalent but have different advantages and drawbacks. In all cases, the calculation of the operator-valued quasi-probability function allows one to compute time-dependent statistical averages of observables. This may be accomplished in practice using a hybrid Molecular Dynamics/Monte Carlo algorithms, which we outline herein.

scholarly journals Experimental Studies of an Eddy Current Transducer with Spatially Periodic Fields

2018 ◽  
pp. 45-50
Author(s):  
B. Gorkunov ◽  
S. Lvov ◽  
Tamer Shaiban ◽  
Y. Borysenko
Keyword(s):  
Eddy Current ◽  
Experimental Studies ◽  
Fixed Frequency ◽  
Current Transducer ◽  
Current Conductor ◽  
Translation Symmetry ◽  
Spatially Periodic ◽  
Transducer Output ◽  
Angular Coordinates ◽  
Eddy Current Transducer

The purpose of this study is to perform a comparative analysis of the experimentally obtained and calculated values of the measuring windings total EMF amplitudes of the eddy current transducer with spatially periodic fields when magnetic and nonmagnetic cylindrical product are placed in it. To realize this goal in the work, a transducer with translational symmetry of excitation magnetic field has been developed. Translation symmetry typical example is the field of a long current conductor. The paper considers quasi-static electromagnetic field with the wavelength that exceeds characteristic transverse dimensions of conductor and cylinder. As the study result it is seen a satisfactory coincidence of the calculated and experimentally obtained values of the EMF of the transducer output signal in the cases of the product absence and with variety of products. As for example for measuring windings with angular coordinates φ = 30° and 60° an error of voltage values difference is less than 10%. The study shows that the advantage of such transducers while operating on one fixed frequency is capability to perform the multi-parameter testing on account of processing of certain amount of some spatial harmonics of excitation field.

scholarly journals Rigorous bounds on dynamical response functions and time-translation symmetry breaking

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Marko Medenjak ◽  
Tomaz Prosen ◽  
Lenart Zadnik
Keyword(s):  
Dynamical Response ◽  
Response Functions ◽  
Xxz Model ◽  
Dynamical Symmetries ◽  
Time Translation ◽  
Spatially Inhomogeneous ◽  
Translation Symmetry ◽  
Local Operators ◽  
Rigorous Bounds ◽  
Translation Symmetry Breaking

Dynamical response functions are standard tools for probing local physics near the equilibrium. They provide information about relaxation properties after the equilibrium state is weakly perturbed. In this paper we focus on systems which break the assumption of thermalization by exhibiting persistent temporal oscillations. We provide rigorous bounds on the Fourier components of dynamical response functions in terms of extensive or local dynamical symmetries, i.e., extensive or local operators with periodic time dependence. Additionally, we discuss the effects of spatially inhomogeneous dynamical symmetries. The bounds are explicitly implemented on the example of an interacting Floquet system, specifically in the integrable Trotterization of the Heisenberg XXZ model.

scholarly journals DISSIPATIVE 2D ELECTRON ON A TORUS IN EXTERNAL MAGNETIC FIELD: TRANSPORT PROPERTIES AND MAGNETIC TRANSLATIONS

1995 ◽  
Vol 09 (24) ◽  
pp. 3229-3240 ◽  
Author(s):  
G. CRISTOFANO ◽  
D. GIULIANO ◽  
G. MAIELLA ◽  
L. VALENTE
Keyword(s):  
Magnetic Field ◽  
Wave Function ◽  
Transport Properties ◽  
Ground State ◽  
Large Time ◽  
Transverse Magnetic ◽  
The Novel ◽  
Translation Operators ◽  
Magnetic Translation ◽  
Electron Ground State

The effect of dissipation on the electron ground state wave function on a torus in the presence of an external transverse magnetic field is analyzed on large time scales [Formula: see text]. Its extension to the multiparticle center of the mass wave function is also given. The novel transport properties of the system are then studied by applying Laughlin gauge argument with the use of the magnetic translation operators.

Sign in / Sign up

Export Citation Format

Share Document