scholarly journals Asymmetric topological pumping in nonparaxial photonics

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Qingqing Cheng ◽  
Huaiqiang Wang ◽  
Yongguan Ke ◽  
Tao Chen ◽  
Ye Yu ◽  
...  
Keyword(s):  
Light Beam ◽  
Optical Waveguides ◽  
Schrodinger Equation ◽  
The Other ◽  
Waveguide Array ◽  
Reverse Process ◽  
Quantum Optical ◽  
Electron Wavefunction ◽  
Optical Analogy ◽  
Unexpected Phenomenon

AbstractTopological photonics was initially inspired by the quantum-optical analogy between the Schrödinger equation for an electron wavefunction and the paraxial equation for a light beam. Here, we reveal an unexpected phenomenon in topological pumping observed in arrays of nonparaxial optical waveguides where the quantum-optical analogy becomes invalid. We predict theoretically and demonstrate experimentally an asymmetric topological pumping when the injected field transfers from one side of the waveguide array to the other side whereas the reverse process is unexpectedly forbidden. Our finding could open an avenue for exploring topological photonics that enables nontrivial topological phenomena and designs in photonics driven by nonparaxiality.

Fabrication and Characterisation of Reverse Proton Exchange Optical Waveguides in Neodymium Doped Lithium Niobate Crystals

2005 ◽  
Vol 480-481 ◽  
pp. 429-436
Author(s):  
M. Domenech ◽  
G. Lifante ◽  
F. Cussó ◽  
A. Parisi ◽  
A.C. Cino ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Optical Waveguides ◽  
Spectroscopic Properties ◽  
Proton Exchange ◽  
Fabrication Process ◽  
The Other ◽  
Ion Plating ◽  
Other Hand ◽  
Channel Waveguides ◽  
Lithium Niobate Crystals

In this work, the complete fabrication process which combines Proton Exchange (PE) and Reverse Proton Exchange (RPE) in Neodymium doped LiNbO3 channel waveguides is reported. To produce the PE-RPE channel waveguides the fabrication of dielectric SiO2 masks had to be implemented. For this propose, we adopted a technique based on the Ion Plating Plasma Assisted Deposition of SiO2 followed by the standard ultraviolet photolithographic patterning. On the other hand, we determined the main optical and spectroscopic properties of Nd3+ ions in the channel waveguides including the study of the lifetime as function as the polarisation.

scholarly journals Observation of Floquet solitons in a topological bandgap

Science ◽  
2020 ◽  
Vol 368 (6493) ◽  
pp. 856-859 ◽  
Author(s):  
Sebabrata Mukherjee ◽  
Mikael C. Rechtsman
Keyword(s):  
Schrödinger Equation ◽  
Topological Insulator ◽  
Kerr Effect ◽  
Schrodinger Equation ◽  
Nonlinear Schrodinger Equation ◽  
Optical Kerr Effect ◽  
Pitaevskii Equation ◽  
Waveguide Array ◽  
Winding Number ◽  
Interparticle Interactions

Topological protection is a universal phenomenon that applies to electronic, photonic, ultracold atomic, mechanical, and other systems. The vast majority of research in these systems has explored the linear domain, where interparticle interactions are negligible. We experimentally observed solitons—waves that propagate without changing shape as a result of nonlinearity—in a photonic Floquet topological insulator. These solitons exhibited distinct behavior in that they executed cyclotron-like orbits associated with the underlying topology. Specifically, we used a waveguide array with periodic variations along the waveguide axis, giving rise to nonzero winding number, and the nonlinearity arose from the optical Kerr effect. This result applies to a range of bosonic systems because it is described by the focusing nonlinear Schrödinger equation (equivalently, the attractive Gross-Pitaevskii equation).

Long tipping times of a quantum rod

2006 ◽  
Vol 84 (1) ◽  
pp. 19-36 ◽  
Author(s):  
Mark B Lundeberg ◽  
Mark RA Shegelski
Keyword(s):  
Quantum State ◽  
Schrodinger Equation ◽  
Center Of Mass ◽  
Edge Length ◽  
The Other ◽  
Late Time ◽  
Time Behaviour ◽  
Complex Energy ◽  
Energy Eigenstates ◽  
Quantum Rod

We calculate the tipping time of a quantum rod that has a height several times that of the edge length of its square base. We use an expression for the tipping time that has heuristic value, and gives the average time at which, upon measurement, the initially balanced rod is found to tip. We use two methods to calculate the tipping time. One method is to examine the "late time" behaviour of the quantum state of the center of mass of the rod by using an equation that has the form of the time-independent Schrödinger equation except that it involves a "complex energy." The other method uses energy resonances in the eigenstates of the Hamiltonian to determine the tipping time. We use the well-known Wentzel–Kramers–Brillouin approximation to calculate the energy eigenstates. With these methods, we obtain expressions for the tipping time that are valid for very long tipping times. PACS Nos.: 03.65.–w, 03.65.Xp

scholarly journals Calculation of Binding Energy and Wave Function for Exotic Hidden-Charm Pentaquark

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
F. Chezani Sharahi ◽  
M. Monemzadeh
Keyword(s):  
Wave Function ◽  
Binding Energy ◽  
Schrödinger Equation ◽  
Schrodinger Equation ◽  
Bound State ◽  
The Other

In this study, pentaquark P c 4380 composed of a baryon Σ c , and a D ¯ ∗ meson is considered. Pentaquark is as a bound state of two-body systems composed of a baryon and a meson. The calculated potential will be expanded and replaced in the Schrödinger equation until tenth sentences of expansion. Solving the Schrödinger equation with the expanded potential of Pentaquark leads to an analytically complete approach. As a consequence, the binding energy E B of pentaquark P c and wave function is obtained. The results E B will be presented in the form of tables so that we can review the existence of pentaquark P c . Then, the wave function will be shown on diagrams. Finally, the calculated results are compared with the other obtained results, and the mass of observing pentaquark P c and the radius of pentaquark are estimated.

scholarly journals A Uniform Heating Technique for Cavity in Volatile Organic Compound (VOC) Removal System Using Slotted Waveguide Array

2021 ◽  
Vol 21 (2) ◽  
pp. 126-133
Author(s):  
Taewoo Yu ◽  
Hyunwook Lee ◽  
Sang-Jun Park ◽  
Sangwook Nam
Keyword(s):  
Organic Compound ◽  
The Other ◽  
Waveguide Array ◽  
Voc Removal ◽  
Impedance Data ◽  
Volatile Organic ◽  
Feeding Structure ◽  
Heating Uniformity ◽  
Slotted Waveguide ◽  
Removal System

In this study, two types of slotted waveguide are designed in the frequency of 2.45 GHz to improve the microwave heating uniformity of a quadrangular prism-shaped cavity in a volatile organic compound (VOC) removal system. Both types adopt the equivalent circuit approach used for a waveguide slot array antenna. The difference between the two types is the slot impedance extraction method of the waveguide slot array: one calculates the impedance taking the cavity structure into account and the other finds it in free space. Both methods show that the heating uniformity is improved by 52% compared with that of the conventional horn-type feeding structure system according to the simulation results. Even though there is no difference in the heating uniformity between the two models, it is confirmed that the slotted waveguide array feeding model designed by using the impedance data of the slot incorporating the cavity (SAWFM<sub>cavity</sub>) has about 6.35 dB better impedance matching characteristics than the other model designed by extracting the impedance data of the slot in free space (SAWFM<sub>free</sub>). Also, it is found that the SAWFM<sub>cavity</sub> shows more stable impedance characteristics with respect to the loading condition than the SAWFM<sub>free</sub>. Therefore, it is concluded that the impedance of the slot should be extracted taking the cavity into account for the design of the slotted waveguide feeding structure since it improves the reflection characteristic as well as the heating uniformity compared with the horn-type feeding structure.

Double Shell Structure of the Periodic System of the Elements

1970 ◽  
Vol 25 (2) ◽  
pp. 210-217 ◽  
Author(s):  
D. Neubert
Keyword(s):  
Schrödinger Equation ◽  
Quantum Number ◽  
Periodic System ◽  
Shell Structure ◽  
Schrodinger Equation ◽  
The Other ◽  
Coulomb Problem ◽  
Other Hand ◽  
Partial Filling ◽  
Symmetry Properties

Abstract A new periodic system of the elements (PSE) is proposed which exhibits symmetry properties not apparent in the conventional arrangement of the elements. By discussing the solutions of the non-relativistic Schrödinger equation for the Coulomb problem it is shown that the PSE might be based on the filling of only four Coulomb shells as compared to the partial filling of up to eight shells in the conventional classification. On the other hand, the multiplicity of the states in the PSE appears to be four as compared to two due to spin in the hydrogen spectrum. A transformation of the PSE-spectrum into the hydrogen spectrum is possible by a rotation in quantum number space.

Predissociation in the spectrum of OH; the vibrational and rotational intensity distribution in flames

1951 ◽  
Vol 208 (1092) ◽  
pp. 63-75 ◽  
Keyword(s):  
Reaction Zone ◽  
Intensity Distribution ◽  
Atmospheric Pressure ◽  
Low Pressure ◽  
The Other ◽  
Spin Component ◽  
Reverse Process ◽  
Free Atoms

In the main 3064 Å system of OH higher rotational levels of bands with v' = 1 and all levels with v' ≥ 2 are affected by a weak predissociation. One spin component of the 2Ʃ + levels is more strongly affected than the other. Of the three molecular states, 4II, 4Ʃ ¯ and 2Ʃ ¯ which could conceivably cause the predissociation, only the 2Ʃ ¯ could produce this effect. The predissociation is observed in the OH bands from a discharge and from the reaction zone of an oxy-acetylene flame at low pressure, and also to some extent in a flame at atmospheric pressure. The predissociation, and its reverse process, a ‘pre-association’, may also affect the vibrational intensity distribution if there is departure from equilibrium. Striking anomalies of this type in hydrogen flames are interpreted in this way. For flames at 1 atm. pressure there appears to be an excess of free atoms in the flame, and at low-pressure emission of radiation from the flame disturbs the equilibrium.

scholarly journals Quantum Energy of a Particle in a Finite-potential Well Based Upon Golden Metric Tensor

2019 ◽  
pp. 1-9
Author(s):  
I. I. Ewa ◽  
S. X. K. Howusu ◽  
L. W. Lumbi
Keyword(s):  
Quantum Theory ◽  
Schrödinger Equation ◽  
Schrodinger Equation ◽  
Energy Levels ◽  
Particle Energy ◽  
The Other ◽  
Laplacian Operator ◽  
Potential Well ◽  
Metric Tensor ◽  
Quantum Energy

In our previous work titled “Riemannian Quantum Theory of a Particle in a Finite-Potential Well", we constructed the Riemannian Laplacian operator and used it to obtain the Riemannian Schrodinger equation for a particle in a finite-potential well. In this work, we solved the golden Riemannian Schrodinger equation analytically to obtain the particle energy. The solution resulted in two expressions for the energy of a particle in a finite-potential well. One of the expressions is for the odd energy levels while the other is for the even energy levels.

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