The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform

Nimrod Moiseyev - One of the best experts on this subject based on the ideXlab platform.

  • non hermitian scattering theory resonant tunneling Probability Amplitude in a quantum dot
    Physical Review B, 2003
    Co-Authors: Hadas Barkay, Edvardas Narevicius, Nimrod Moiseyev
    Abstract:

    We suggest a mechanism for the sharp phase change in the transition-Probability Amplitude of electrons scattered through a quantum dot. The proposed mechanism is a single electron phenomenon that involves interference between the two-dimensional resonances of the quantum dot. The dimensionality of the problem plays a key role in our mechanism.

  • complex density Probability in non hermitian quantum mechanics interpretation and a formula for resonant tunneling Probability Amplitude
    Physical Review A, 2001
    Co-Authors: Hadas Barkay, Nimrod Moiseyev
    Abstract:

    Non-Hermitian quantum mechanics has been developed to study the dynamics of nuclear, atomic, and molecular sys- tems that can be prepared in metastable finite-lifetime states ~so-called resonance states !@ 1,2# for the study of delocaliza- tion phenomenon which is relevant in different fields, such as bacteria populations, vortex spinning in superconductors, and for the study of the stability conditions of the solutions of hydrodynamical problems @3,4#. In cases where resonance phenomena are studied, the Hamiltonians are non-Hermitian due to the specific boundary conditions that are imposed on the solutions of the Schrodinger equation. The asymptotic solutions should be exponential divergent wave functions ~known as Siegert functions!. In other cases @3,4# the Hamil- tonian is non-Hermitian due to the inclusion of a non- Hermitian operator such as a vii, while the boundary con- ditions of ''conventional'' Hermitian quantum mechanics are kept. There is a way to unify the two types of non-Hermitian quantum problems. Upon complex scaling, i.e., x !x exp(iu), the exponentially divergent metastable reso- nance eigenfunctions become square integrable and thereby become part of the generalized Hilbert space @2#. Therefore, the resonances are the eigenfunctions of a complex scaled non-Hermitian Hamiltonian with the same boundary condi- tions as in the conventional Hermitian quantum mechanics. Let us denote the complex non-Hermitian Hamiltonian by H ˆ . A matrix representation of H ˆ ~denoted by H) is obtained by using a finite number of orthogonal functions as a basis set. Since the usual boundary conditions are applied the basis functions can be square integrable or periodic functions. The right and left eigenfunctions of H ˆ, which are defined asC j R and C j , are associated with the right and left eigenvectors of H:

Daniel T Cassidy - One of the best experts on this subject based on the ideXlab platform.

  • a Probability Amplitude transfer matrix method for calculating the distribution of light in semiconductor lasers
    IEEE Journal of Quantum Electronics, 2003
    Co-Authors: G B Morrison, Daniel T Cassidy
    Abstract:

    The energy density in a semiconductor laser cavity plays an important role in determining the above-threshold properties of the laser. There is, therefore, a need for accurate physical models for the distribution of light within laser cavities. This paper applies the Probability-Amplitude method for calculating distributed feedback laser spectra to the problem of calculating the distribution of light within a laser cavity. Results of the calculations are shown to be in agreement with results obtained by other methods, and physical explanations are given for some of the interesting aspects of the distributions of light in semiconductor lasers. The Probability-Amplitude model for calculation of the distribution of light has advantages over many other models in that it includes both the standing-wave effect and the quantum mechanical nature of the spontaneous emission within the cavity.

  • Facet phases and sub-threshold spectra of DFB lasers: spectral extraction, features, explanations and verification
    IEEE Journal of Quantum Electronics, 2001
    Co-Authors: G B Morrison, Daniel T Cassidy, D.m. Bruce
    Abstract:

    The sub-threshold spectra of distributed feedback (DFB) lasers are heavily influenced by the phase of the internal grating with respect to the end facets. In this paper, we document features commonly observed in sub-threshold spectra and explain these features as manifestations of the facet phases. We extract estimates of facet phases by fitting a Probability-Amplitude transfer-matrix model to spectra from six truncated-well DFB lasers, and use the Probability-Amplitude model to document, isolate, and explain the sub-threshold spectral dependence on facet phase. To verify the accuracy of the approach that we have taken, we compare estimates of the facet phases from the fits to independent measurements of the facet phases using a scanning photoluminescence method. The results from the two methods are compared and are found to be in agreement. The agreement validates our use of the Probability-Amplitude model in this paper to explain laser facet phase phenomena.

  • a Probability Amplitude transfer matrix model for distributed feedback laser structures
    IEEE Journal of Quantum Electronics, 2000
    Co-Authors: G B Morrison, Daniel T Cassidy
    Abstract:

    Two different treatments of spontaneous emission in distributed-feedback (DFB) lasers were found in the literature, but adequate explanations for the different treatments were not found. Using an approach that allows comparison of the two different treatments of spontaneous emission, we show that the different treatments can lead to different spectral predictions. The difference in spectral predictions is negligible in Fabry-Perot lasers and index-coupled DFB lasers. However, in truncated-well gain-coupled DFB lasers, the difference between the two treatments is noticeable, and one treatment is markedly better at fitting to data. The treatment that best fits the data is also the treatment that makes sense quantum-mechanically.

Hadas Barkay - One of the best experts on this subject based on the ideXlab platform.

  • non hermitian scattering theory resonant tunneling Probability Amplitude in a quantum dot
    Physical Review B, 2003
    Co-Authors: Hadas Barkay, Edvardas Narevicius, Nimrod Moiseyev
    Abstract:

    We suggest a mechanism for the sharp phase change in the transition-Probability Amplitude of electrons scattered through a quantum dot. The proposed mechanism is a single electron phenomenon that involves interference between the two-dimensional resonances of the quantum dot. The dimensionality of the problem plays a key role in our mechanism.

  • complex density Probability in non hermitian quantum mechanics interpretation and a formula for resonant tunneling Probability Amplitude
    Physical Review A, 2001
    Co-Authors: Hadas Barkay, Nimrod Moiseyev
    Abstract:

    Non-Hermitian quantum mechanics has been developed to study the dynamics of nuclear, atomic, and molecular sys- tems that can be prepared in metastable finite-lifetime states ~so-called resonance states !@ 1,2# for the study of delocaliza- tion phenomenon which is relevant in different fields, such as bacteria populations, vortex spinning in superconductors, and for the study of the stability conditions of the solutions of hydrodynamical problems @3,4#. In cases where resonance phenomena are studied, the Hamiltonians are non-Hermitian due to the specific boundary conditions that are imposed on the solutions of the Schrodinger equation. The asymptotic solutions should be exponential divergent wave functions ~known as Siegert functions!. In other cases @3,4# the Hamil- tonian is non-Hermitian due to the inclusion of a non- Hermitian operator such as a vii, while the boundary con- ditions of ''conventional'' Hermitian quantum mechanics are kept. There is a way to unify the two types of non-Hermitian quantum problems. Upon complex scaling, i.e., x !x exp(iu), the exponentially divergent metastable reso- nance eigenfunctions become square integrable and thereby become part of the generalized Hilbert space @2#. Therefore, the resonances are the eigenfunctions of a complex scaled non-Hermitian Hamiltonian with the same boundary condi- tions as in the conventional Hermitian quantum mechanics. Let us denote the complex non-Hermitian Hamiltonian by H ˆ . A matrix representation of H ˆ ~denoted by H) is obtained by using a finite number of orthogonal functions as a basis set. Since the usual boundary conditions are applied the basis functions can be square integrable or periodic functions. The right and left eigenfunctions of H ˆ, which are defined asC j R and C j , are associated with the right and left eigenvectors of H:

G B Morrison - One of the best experts on this subject based on the ideXlab platform.

  • a Probability Amplitude transfer matrix method for calculating the distribution of light in semiconductor lasers
    IEEE Journal of Quantum Electronics, 2003
    Co-Authors: G B Morrison, Daniel T Cassidy
    Abstract:

    The energy density in a semiconductor laser cavity plays an important role in determining the above-threshold properties of the laser. There is, therefore, a need for accurate physical models for the distribution of light within laser cavities. This paper applies the Probability-Amplitude method for calculating distributed feedback laser spectra to the problem of calculating the distribution of light within a laser cavity. Results of the calculations are shown to be in agreement with results obtained by other methods, and physical explanations are given for some of the interesting aspects of the distributions of light in semiconductor lasers. The Probability-Amplitude model for calculation of the distribution of light has advantages over many other models in that it includes both the standing-wave effect and the quantum mechanical nature of the spontaneous emission within the cavity.

  • Facet phases and sub-threshold spectra of DFB lasers: spectral extraction, features, explanations and verification
    IEEE Journal of Quantum Electronics, 2001
    Co-Authors: G B Morrison, Daniel T Cassidy, D.m. Bruce
    Abstract:

    The sub-threshold spectra of distributed feedback (DFB) lasers are heavily influenced by the phase of the internal grating with respect to the end facets. In this paper, we document features commonly observed in sub-threshold spectra and explain these features as manifestations of the facet phases. We extract estimates of facet phases by fitting a Probability-Amplitude transfer-matrix model to spectra from six truncated-well DFB lasers, and use the Probability-Amplitude model to document, isolate, and explain the sub-threshold spectral dependence on facet phase. To verify the accuracy of the approach that we have taken, we compare estimates of the facet phases from the fits to independent measurements of the facet phases using a scanning photoluminescence method. The results from the two methods are compared and are found to be in agreement. The agreement validates our use of the Probability-Amplitude model in this paper to explain laser facet phase phenomena.

  • a Probability Amplitude transfer matrix model for distributed feedback laser structures
    IEEE Journal of Quantum Electronics, 2000
    Co-Authors: G B Morrison, Daniel T Cassidy
    Abstract:

    Two different treatments of spontaneous emission in distributed-feedback (DFB) lasers were found in the literature, but adequate explanations for the different treatments were not found. Using an approach that allows comparison of the two different treatments of spontaneous emission, we show that the different treatments can lead to different spectral predictions. The difference in spectral predictions is negligible in Fabry-Perot lasers and index-coupled DFB lasers. However, in truncated-well gain-coupled DFB lasers, the difference between the two treatments is noticeable, and one treatment is markedly better at fitting to data. The treatment that best fits the data is also the treatment that makes sense quantum-mechanically.

Yong Fei Yang - One of the best experts on this subject based on the ideXlab platform.

  • An Improved Quantum Genetic Algorithm Based on Population Partition and Dynamic Probability Amplitude
    Advances in Natural Computation Fuzzy Systems and Knowledge Discovery, 2020
    Co-Authors: Cheng Yao Shi, Zhao Cheng Xuan, Chao Yang, Yong Fei Yang
    Abstract:

    Aiming at the problem that quantum genetic algorithm is easy to fall into local optimization in the process of function optimization under the original framework, an improved quantum genetic algorithm using population partition method and dynamic inverse Probability Amplitude strategy is proposed. In the process of optimization, the improved algorithm utilizes the superior individuals in each generation of populations to construct a population genotype suitable for evolution through the individual binary form. On this basis, replace the inferior individuals in the population with a certain proportion, and then construct a number of similar individuals that tend to the genotype of the superior individual. Therefore, the algorithm can continuously improve the adaptability of the problem and gradually converge to the optimal solution. At the same time, for the premature or local optimization problem that the algorithm may be trapped, in the period of algorithm stagnation, the population diversity is enriched by resetting the genotype of some individuals and narrowing the search space by using the current optimal solution.

  • ICNC-FSKD - An Improved Quantum Genetic Algorithm Based on Population Partition and Dynamic Probability Amplitude
    Advances in Natural Computation Fuzzy Systems and Knowledge Discovery, 2019
    Co-Authors: Zhao Cheng Xuan, Chao Yang, Yong Fei Yang
    Abstract:

    Aiming at the problem that quantum genetic algorithm is easy to fall into local optimization in the process of function optimization under the original framework, an improved quantum genetic algorithm using population partition method and dynamic inverse Probability Amplitude strategy is proposed. In the process of optimization, the improved algorithm utilizes the superior individuals in each generation of populations to construct a population genotype suitable for evolution through the individual binary form. On this basis, replace the inferior individuals in the population with a certain proportion, and then construct a number of similar individuals that tend to the genotype of the superior individual. Therefore, the algorithm can continuously improve the adaptability of the problem and gradually converge to the optimal solution. At the same time, for the premature or local optimization problem that the algorithm may be trapped, in the period of algorithm stagnation, the population diversity is enriched by resetting the genotype of some individuals and narrowing the search space by using the current optimal solution.