scholarly journals HEISENBERG INTEGER SPIN CHAINS IN A UNIFORM MAGNETIC FIELD

2002 ◽  
Vol 16 (09) ◽  
pp. 1363-1379 ◽  
Author(s):  
L. CAMPOS VENUTI ◽  
E. ERCOLESSI ◽  
G. MORANDI ◽  
P. PIERI ◽  
M. RONCAGLIA

We investigate both numerically and analytically the behavior of a spin-1 antiferromagnetic isotropic Heisenberg chain in an external uniform magnetic field. Extensive DMRG studies of chains up to N = 80 sites extend previous analyses and obtain the zero-temperature correlation functions. We argue that, despite the presence of a magnetic field, the model is still well described by an O(3) nonlinear σ-model. A saddle-point analysis, that also includes Gaussian fluctuations, is developed for the latter both at zero and finite temperatures. Its predictions are compared with those of the numerical analysis and with the existing experimental literature.

2013 ◽  
Vol 579-580 ◽  
pp. 706-710
Author(s):  
Peng Huang ◽  
Chun Fu Gao ◽  
Xin Sheng He ◽  
Hai Feng Ji

As there are relatively fewer studies about non-uniform magnetic field design and numerical analysis, a model of wedge pole electromagnet has designed and analyzed based on the traditional electromagnet design method. The effects of coil turn, conductor sectional and electric current density on magnetic field intensity had also designed and calculated. The design and numerical analysis of wedge pole electromagnet were conducted which adopted the finite element simulation and optimal design method. The magnetic induction intensity for the wedge pole electromagnet in different positions of the air gap had analog calculated. The simulated and test results for distributing magnetic field can be well corresponded by considering the effect of eddy loss, material and machining errors of electromagnetic. The result indicated that the method of simulation is correct and practical. The method provides a reliable simulation analysis and empirical data for the design of non-uniform magnetic field.


2008 ◽  
Vol 06 (06) ◽  
pp. 1213-1222
Author(s):  
JIN-LIANG GUO ◽  
JIE SONG ◽  
HE-SHAN SONG

We study quantum teleportation by using 1D optical lattice for two particles with nonlinear coupling in an external uniform magnetic field as resources via the standard teleportation protocol T0. The effects of linear coupling J, nonlinear coupling K and magnetic field B on the average fidelity are investigated in detail. It is found that increasing |K| is not only very helpful for enhancing the average fidelity, but also beneficial to improving the critical temperature Tf and magnetic field Bf, beyond which quantum teleportation is inferior to classical communication protocol.


1993 ◽  
Vol 94 (1) ◽  
pp. 11-38 ◽  
Author(s):  
F. Colomo ◽  
A. G. Izergin ◽  
V. E. Korepin ◽  
V. Tognetti

Fluids ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 177 ◽  
Author(s):  
Tagawa

Linear stability analysis of liquid metal flow driven by a constant pressure gradient in an insulating rectangular duct under an external uniform magnetic field was carried out. In the present analysis, since the Joule heating and induced magnetic field were neglected, the governing equations consisted of the continuity of mass, momentum equation, Ohm’s law, and conservation of electric charge. A set of linearized disturbance equations for the complex amplitude was decomposed into real and imaginary parts and solved numerically with a finite difference method using the highly simplified marker and cell (HSMAC) algorithm on a two-dimensional staggered mesh system. The difficulty of the complex eigenvalue problem was circumvented with a Newton—Raphson method during which its corresponding eigenfunction was simultaneously obtained by using an iterative procedure. The relation among the Reynolds number, the wavenumber, the growth rate, and the angular frequency was successfully obtained for a given value of the Hartmann number as well as for a direction of external uniform magnetic field.


Author(s):  
Haim H. Bau ◽  
Jianzhong Zhu ◽  
Shizhi Qian ◽  
Yu Xiang

The magneto hydrodynamic fluidic network’s basic building blocks are conduits equipped with two electrodes positioned on opposing walls. The entire device is either subjected to an external uniform magnetic field or fabricated within a magnetic material. When a prescribed potential difference is applied across each electrode pair, it induces current in the liquid (assumed to be a weakly conductive). The current interacts with the magnetic field to produce a Lorentz force that is perpendicular to both the directions of the current and the magnetic field. Analogously with electric circuits, by judicious application of the potential differences at various branches, one can direct liquid flow in any desired way and rate without a need for mechanical pumps or valves. By equipping the network branches with additional, interior electrodes, the branches double as stirrers capable of generating chaotic advection. The paper describes the basic building blocks for such a network, the operation of these branches as stirrers, a general theory for the analysis and control of fluidic magneto-hydrodynamic networks, and an example of a network fabricated with low temperature, co-fired ceramic tapes.


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