scholarly journals Effective dynamics of two-dimensional Bloch electrons in external fields derived from symmetry

2019 ◽  
Vol 100 (12) ◽  
Author(s):  
E. A. Fajardo ◽  
R. Winkler
Keyword(s):  
Two Dimensional ◽  
External Fields ◽  
Effective Dynamics ◽  
Bloch Electrons

scholarly journals Nematic topological defects positionally controlled by geometry and external fields

2018 ◽  
Vol 9 ◽  
pp. 109-118 ◽  
Author(s):  
Pavlo Kurioz ◽  
Marko Kralj ◽  
Bryce S Murray ◽  
Charles Rosenblatt ◽  
Samo Kralj
Keyword(s):  
Electric Field ◽  
Topological Charge ◽  
Order Parameter ◽  
Topological Defects ◽  
Two Dimensional ◽  
External Fields ◽  
Nematic Ordering ◽  
Spatial Positioning ◽  
A Charge ◽  
The Impact

Using a Landau–de Gennes approach, we study the impact of confinement topology, geometry and external fields on the spatial positioning of nematic topological defects (TDs). In quasi two-dimensional systems we demonstrate that a confinement-enforced total topological charge of m > 1/2 decays into elementary TDs bearing a charge of m = 1/2. These assemble close to the bounding substrate to enable essentially bulk-like uniform nematic ordering in the central part of a system. This effect is reminiscent of the Faraday cavity phenomenon in electrostatics. We observe that in certain confinement geometries, varying the correlation length size of the order parameter could trigger a global rotation of an assembly of TDs. Finally, we show that an external electric field could be used to drag the boojum fingertip towards the interior of the confinement cell. Assemblies of TDs could be exploited as traps for appropriate nanoparticles, opening several opportunities for the development of functional nanodevices.

scholarly journals M-theory and two-dimensional effective dynamics

2000 ◽  
Vol 569 (1-3) ◽  
pp. 661-679 ◽  
Author(s):  
N.D. Lambert ◽  
P.C. West
Keyword(s):  
Two Dimensional ◽  
Effective Dynamics ◽  
M Theory
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