Layer Edge States Stabilized by Internal Electric Fields in Two-Dimensional Hybrid Perovskites

Abstract We give an interpretation of the holographic correspondence between two-dimensional BF theory on the punctured disk with gauge group PSL(2, ℝ) and Schwarzian quantum mechanics in terms of a Drinfeld-Sokolov reduction. The latter, in turn, is equivalent to the presence of certain edge states imposing a first class constraint on the model. The constrained path integral localizes over exceptional Virasoro coadjoint orbits. The reduced theory is governed by the Schwarzian action functional generating a Hamiltonian S1-action on the orbits. The partition function is given by a sum over topological sectors (corresponding to the exceptional orbits), each of which is computed by a formal Duistermaat-Heckman integral.

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Simulation of Two-Dimensional Nematic Director Structures in Inhomogeneous Electric Fields

Molecular Crystals and Liquid Crystals ◽

10.1080/00268949108033379 ◽

1991 ◽

Vol 198 (1) ◽

pp. 15-28 ◽

Cited By ~ 22

Author(s):

Gunther Haas ◽

Henning Wöhler ◽

Michael W. Fritsch ◽

Dieter A. Mlynski

Keyword(s):

Electric Fields ◽

Two Dimensional ◽

Nematic Director

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Numerical study of electric field effects on the deformation of two-dimensional liquid drops in simple shear flow at arbitrary Reynolds number

Journal of Fluid Mechanics ◽

10.1017/s0022112009006442 ◽

2009 ◽

Vol 626 ◽

pp. 367-393 ◽

Cited By ~ 32

Author(s):

STEFAN MÄHLMANN ◽

DEMETRIOS T. PAPAGEORGIOU

Keyword(s):

Steady State ◽

Shear Flow ◽

Electric Field ◽

Electric Fields ◽

Simple Shear ◽

Simple Shear Flow ◽

Physical Parameters ◽

Shear Stresses ◽

Two Dimensional ◽

Liquid Drops

The effect of an electric field on a periodic array of two-dimensional liquid drops suspended in simple shear flow is studied numerically. The shear is produced by moving the parallel walls of the channel containing the fluids at equal speeds but in opposite directions and an electric field is generated by imposing a constant voltage difference across the channel walls. The level set method is adapted to electrohydrodynamics problems that include a background flow in order to compute the effects of permittivity and conductivity differences between the two phases on the dynamics and drop configurations. The electric field introduces additional interfacial stresses at the drop interface and we perform extensive computations to assess the combined effects of electric fields, surface tension and inertia. Our computations for perfect dielectric systems indicate that the electric field increases the drop deformation to generate elongated drops at steady state, and at the same time alters the drop orientation by increasing alignment with the vertical, which is the direction of the underlying electric field. These phenomena are observed for a range of values of Reynolds and capillary numbers. Computations using the leaky dielectric model also indicate that for certain combinations of electric properties the drop can undergo enhanced alignment with the vertical or the horizontal, as compared to perfect dielectric systems. For cases of enhanced elongation and alignment with the vertical, the flow positions the droplets closer to the channel walls where they cause larger wall shear stresses. We also establish that a sufficiently strong electric field can be used to destabilize the flow in the sense that steady-state droplets that can exist in its absence for a set of physical parameters, become increasingly and indefinitely elongated until additional mechanisms can lead to rupture. It is suggested that electric fields can be used to enhance such phenomena.

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Edge states in a two-dimensional honeycomb lattice of massive magnetic skyrmions

Physical Review B ◽

10.1103/physrevb.98.180407 ◽

2018 ◽

Vol 98 (18) ◽

Cited By ~ 14

Author(s):

Z.-X. Li ◽

C. Wang ◽

Yunshan Cao ◽

Peng Yan

Keyword(s):

Honeycomb Lattice ◽

Two Dimensional ◽

Edge States ◽

Magnetic Skyrmions

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Dual-mode of topological rainbow in gradual photonic heterostructures

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac37df ◽

2021 ◽

Author(s):

Mingxing Li ◽

Yueke Wang ◽

Mengjia Lu ◽

Tian Sang

Keyword(s):

Finite Element Method ◽

Finite Element Method Simulation ◽

Two Dimensional ◽

Edge States ◽

Dual Mode ◽

Strong Robustness ◽

Mode Excitation ◽

Simulation Results ◽

Photonic States ◽

Sandwiched Structure

Abstract In this letter, a method to realize the topological rainbow trapping is presented, which is composed of gradual ordinary-topological-ordinary heterostructures based on two-dimensional photonic crystals with C-4 symmetry. In the proposed sandwiched structure, the two coupled topological edge states with different frequencies are separated and trapped in different positions, due to group velocity of near to zero. We have achieved the dual-mode of topological rainbow in one structure, which broadens the bandwidth. Besides, the dual-mode of topological rainbow under one mode excitation is also realized by using a simple bend design. The immunity to defects is also investigated and it is found our slowing light system has strong robustness. Finite Element Method simulation results verify our idea, and our work opens up a new way for frequency routing and broadband operation of topological photonic states.

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