arXiv subjects

M. Akbari-Moghanjoughi

Publications and source records attributed to M. Akbari-Moghanjoughi.

At least 19 recordsLinked to original sources

arXiv2024

Diffusive Decay of Collective Quantum Excitations in Electron Gas

In this work the multistream quasiparticle model of collective electron excitations is used to study the energy-density distribution of collective quantum excitations in an interacting electron gas with arbitrary degree of degeneracy. Generalized relations for the probability current and energy density distributions is obtained which reveals a new interesting quantum phenomenon of diffusive decay of pure quasiparticle states at microscopic level. The effects is studied for various cases of free quasiparticles, quasiparticle in an infinite square-well potential and half-space collective excitations. It is shown that plasmon excitations have the intrinsic tendency to decay into equilibrium state with uniform energy density spacial distribution. It is found that plasmon levels of quasipaticle in a square-well potential are unstable decaying into equilibrium state due to the fundamental property of collective excitations. The decay rates of pure plasmon states are determined analytically. Moreover, for damped quasiparticle excitations the non-vanishing probability current divergence leads to imaginary energy density resulting in damping instability of energy density dynamic. The pronounced energy density valley close to half-space boundary at low level excitations predicts attractive force close to the surface. Current research can have implications with applications in plasmonics and related fields. Current analysis can be readily generalized to include external potential and magnetic field effects.

cond-mat.mes-hall↗

arXiv2023

Deterministic Quantum Field Trajectories and Macroscopic Effects

In this work the root to macroscopic quantum effects is revealed based on the quasiparticle model of collective excitations in an arbitrary degenerate electron gas. The $N$-electron quantum system is considered as $N$ streams coupled, through the Poisson's relation, which are localized in momentum space rather than electron localization in real space, assumed in ordinary many body theories. Using a new wavefunction representation, the $N+1$-coupled system is reduced to simple pseudoforce equations via quasiparticle (collective quantum) model leading to a generalized matter wave dispersion relation. It is shown that the resulting dual lengthscale de Broglie's matter wave theory predicts macroscopic quantum effects and deterministic field trajectories for charges moving in the electron gas due to the coupling of the electrostatic field to the local electron number density. It is remarked that any quantum many body system composed of large number of interacting particles acts as a dual arm device controlling the microscopic single particle effects with one hand and the macroscopic phenomena with the other. Current analysis can be further extended to include the magnetic potential and spin exchange effects. Present model can also be used to confirm macroscopic entanglement of charged particles embedded in a quantum electron fluid.

quant-ph↗

arXiv2023

Plasmon Oscillations and de Broglie's Matter Waves Instabilities

In this research we study the effect of matter-wave instability on electron beam transport with arbitrary degree of degeneracy. Particular class of solutions of the Schrödinger-Poisson system is used to model the electron-beam transport at constant speed. It is shown that such electron-beam is described by a coupled driven pseudoforce system solution of which leads to plasmon excitations with dual wave-particle character. The fundamental quantum mechanical de Broglie relation is found to be due to the resonant interaction of particle-like plasmon excitation branch with the electron beam drift. We further obtain a generalized double lengthscale de Broglie wave-particle relation through which various beam-plasmon instability is studied in this model. The quantum charge screening and the chemical potential effects on the matter-wave formation and instabilities are discussed in detail and the well-known Aharonov-Bohm effect is revisited in current quantum hydrodynamic model. Current research may further illuminate the origin of matter-wave in quantum mechanics and lead to clear understanding of novel wave-particle interactions.

quant-ph↗

arXiv2023

Plasmon Mediated Electron Beam Transport in Quantum Plasma

Starting from the quantum hydrodynamic model and transforming to the coupled driven pseudoforce system the plasmonic excitations of electron beam with arbitrary degree of degeneracy are studied. Using the conventional normal-mode analysis a dual-length-scale wavefunction theory for a monochromatic electron beam is developed. The beam plasmon excitations are shown to have both wave and particle character, de Broglie wavenumbers of which depend on various parameters such as average beam speed, the chemical potential, the charge screening and the background electrostatic energy. The deterministic single electron dynamics in the beam is investigated using the dual-wavelength electrostatic potential energy. It is shown that electrons can be either trapped or traveling along the beam direction depending on the ambient plasma parameter values. The problem of monochromatic beam transport through binary as well as ternary metallic configurations are investigated and some technological applications of these system are pointed out. The theory is extended to multistream phenomenon and electron beam transport through multimedia junction. We believe that current study can have major impact on understanding of the quantum beam-plasma interactions and instabilities and can further elucidate the mechanisms involving in the collective quantum wave-particle phenomena.

physics.plasm-ph↗

arXiv2023

Quantum Interference and Phase Mixing in Multistream Plasmas

In this paper the kinetic corrected Schrödinger-Poisson model is used to obtain the pseudoforce system in order to study variety of streaming electron beam-plasmon interaction effects. The noninteracting stream model is used to investigate the quantum electron beam interference and electron fluid Aharonov-Bohm effects. The model is further extended to interacting two-stream quantum fluid model in order to investigate the orbital quasiparticle velocity, acceleration and streaming power. It is shown that quantum phase mixing in the two-stream model is due to quasiparticle conduction band overlap caused by the Doppler shift in streaming electron de Broglie wavenumbers, a phenomenon which is also known to be a cause for two-stream plasma instability. However, in this case the phase mixing leads to some novel phenomena like stream merging and backscattering. To show the effectiveness of model, it is used to investigate the electron beam-phonon and electron beam-lattice interactions in different beam, ion and lattice parametric configurations. Current density of beam is studied in spatially stable and damping quasiparticle orbital for different symmetric and asymmetric momentum-density arrangements. These basic models may be helpful in better understanding of quantum phase mixing and scattering at quantum level and can be elaborated to study electromagnetic electron beam-plasmon interactions in complex quantum plasmas.

physics.plasm-ph↗

arXiv2023

Collective Quantum Approach to Surface Plasmon Resonance Effect

In this research we present a theory of the surface plasmon resonance (SPR) effect based on the dual length-scale driven damped collective quantum oscillations of the spill-out electrons in plasmonic material surface. The metallic electron excitations are modeled using the Hermitian effective Schrödinger-Poisson system, whereas, the spill-out electron excitations are modeled via the damped non-Hermitian effective Schrödinger-Poisson system adapted appropriately at the metal-vacuum interface. It is shows that, when driven by external field, the system behaves like the driven damped oscillator in wavenumber domain, quite analogous to the driven damped mechanical oscillation in frequency domain, leading to the collective surface spill-out electron excitation resonance. In this model the resonance occurs when the wavenumber of the driving pseudoforce matches that of the surface plasmon excitations which can be either due to single-electrons or collective effects. Current theory of SPR is based on longitudinal electrostatic excitations of the surface electrons, instead of the polariton excitation parallel to the metal-dielectric or metal-vacuum surface. Current theory may also be extended to use for the localized surface plasmon resonance (LSPR) in nanometer sized metallic surfaces in non-planar geometry. A new equation of state (EoS) for the plasmon electron number density in quantum plasmas is obtained which limits the plasmonic effects in high-density low-temperature electron gas regime, due to small transition probability of electrons to the plasmon energy band.

cond-mat.mes-hall↗

arXiv2023

Energy Band Structure of Relativistic Quantum Plasmon Excitation

In this paper we use the effective Schrödinger-Poisson and square-root Klein-Gordon-Poisson models to study the quantum and relativistic quantum energy band structure of finite temperature electron gas in a neutralizing charge background. Based the plasmon band gap appearing above the Fermi level, new definitions on plasmonic excitations and plasma parameters in a wide electron temperature-density regime is suggested. The new equation of state (EoS) for excited electrons to the plasmon band leads to novel aspects of relativistic collective quantum excitations such as the plasmon black-out and quantum pressure collapse which are studied using both non-relativistic and relativistic quantum models. The plasmon black-out effect may be used to explain why metallic elements do not show collective behavior at low temperatures. The model can be used to predict phases of matter in which the plasmonic activities is shut down, hence, it may behave like a mysterious dark matter. On the other hand, the energy band structure model predicts the plasmon pressure collapse in temperature-density coordinates matching that of a white dwarf star. The prediction of energy band structure of collective quantum excitations may have direct implications for the inertial confinement fusion (ICF), the EoS of warm dense matter (WDM) and evolution of stellar and other unknown cosmological structures. It is found that predictions of non-relativistic and relativistic quantum excitation models closely match up to temperature-density of degenerate stars which confirms the relevance of non-relativistic plasmon models used in the warm and dense matter regime. The effect of positron on band structure of collective quantum excitations is also studied.

physics.plasm-ph↗

arXiv2022

Plasmonic Dielectric Response of Finite Temperature Electron Gas

In this research we report the dielectric response of a finite temperature electron gas, electrostatically interacting with both external and self-induced plasmonic fields, in the well-known random phase approximation. The generalized energy dispersion relation which incorporates the plasmonic band structure is used to calculate the Lindhard dielectric response of homogenous electron gas from which many important physical functionals, such as the structure factor, loss function, screening potential, optical reflectivity and electronic stopping power are deduced. The present dual length-scale theory of dielectric response incorporates both single electron as well as collective electrostatic oscillation of electrons which, due to the Van-Hove-like singularity at plasmon wavenumber, shows distinct features of plasmonic response to electromagnetic interactions of the electron gas with arbitrary degree of electron degeneracy. It is shown that the static impurity charge screening potential is oscillatory Lennard-Jones-type attractive potential which is quite different from both predicted by the Conventional noninteracting Lindhard theory and the Shukla-Eliasson attractive potential obtained from quantum hydrodynamic approach. It is also revealed that due to resonant electron-plasmon interactions and multi-pole structure of the electronic response function the Landau damping region is scattered. The findings of current research may have important implications for a wide range of physical phenomena relevant to a broad nonrelativistic electron density-temperature regime, from the laboratory scale semiconductors and nanoelectronic technology to the warm dense matter state.

physics.plasm-ph↗

arXiv2021

Energy Band Structure of Multistream Quantum Electron System

In this paper, using the quantum multistream model, we develop a method to study the electronic band structure of plasmonic excitations in streaming electron gas with arbitrary degree of degeneracy. The multifluid quantum hydrodynamic model is used to obtain $N$-coupled pseudoforce differential equation system from which the energy band structure of plasmonic excitations is calculated. It is shown that inevitable appearance of energy bands separated by gaps can be due to discrete velocity filaments and their electrostatic mode coupling in the electron gas. Current model also provides an alternative description of collisionless damping and phase mixing, i.e., collective scattering phenomenon within the energy band gaps due to mode coupling between wave-like and particle-like oscillations. The quantum multistream model is further generalized to include virtual streams which is used to calculate the electronic band structure of one-dimensional plasmonic crystals. It is remarked that, unlike the empty lattice approximation in free electron model, energy band gaps exist in plasmon excitations due to the collective electrostatic interactions between electrons. It is also shown that the plasmonic band gap size at first Brillouin zone boundary maximizes at the reciprocal lattice vector, $G$, close to metallic densities. Furthermore, the electron-lattice binding and electron-phonon coupling strength effects on the electronic band structure are discussed. It is remarked that inevitable formation of energy band structure is a general characteristics of various electromagnetically and gravitationally coupled quantum multistream systems.

physics.plasm-ph↗

arXiv2021

Collective Free Electron Excitations in Half-Space Configuration

Current research presents an innovative model of half-space plasmon excitations for electron gas of arbitrary degeneracy in an ambient jellium-like positive background . The linearized Schrödinger-Poisson system is used to derive effective coupled pseudoforce and damped pseudoforce system of second-order differential equations from which the state functions such as the electron probability density and electrostatic potential energy are calculated and the appropriate half-space equilibrium plasmon excitation wave-functions are constructed. Current model of half-space finite temperature electron plasmon reveals many interesting features not present in previous studies. This model benefits a dual length scale character of quantum plasmon excitations taking into account the detailed electrostatic interactions between single electrons and their collective entity in an unmagnetized arbitrary degeneracy electron gas. The interaction of these length scales is remarked to lead to the formation of well defined miniature periodic density fringes in the gas which are modulated over the envelop density pattern and causes the presence of an electron halo in front of the physical jellium boundary of the system. A novel attractive Lennard-Jones-like potential energy forms in front of the boundary for parametric density-temperature region relevant to the strongly doped N-type semiconductors as well as metallic surfaces. The later effect may appropriately explain the Casimir-Polder-like forces between parallel metallic plates in vacuum.

physics.plasm-ph↗

arXiv2021

Resonant Electron-Plasmon Interactions in Drifting Electron Gas

In this paper we investigate the resonant electron-plasmon interactions in a drifting electron gas of arbitrary degeneracy. The kinetic corrected quantum hydrodyanmic model is transformed into the effective Schrödinger-Poisson model and driven coupled pseudoforce system is obtained via the separation of variables from the appropriately linearized system. It is remarked that in the low phase-speed kinetic regime the characteristic particle-like plasmon branch is profoundly affected by this correction which is a function of the electron number density and temperature. We also present an alternative explanation of the quantum wave-particle duality as a direct consequence of resonant electron-plasmon interaction (electron murmuration). In this picture drifting electrons are resonantly scattered by spatial electrostatic energy distribution, characterizing them by the de Broglie's oscillations. The phase-shift and amplitude of excitations in damped driven pseudoforce system is derived and their variations in terms of normalized chemical potential and electron temperature is studied. In particular we investigate the kinetic correction effect on energy dispersion relation in the electron gas in detail. It is revealed that only the low phase-speed branch of the dispersion curve is significantly affected by the kinetic correction. It is also found that increase in the electron number density leads to increase in effective mass and consequently decrease in electron mobility while the increase in the electron temperature has the converse effect. The kinetic correction also significantly lowers the plasmon conduction band. Current model may be further elaborated to investigate the beam-plasmon interaction and energy exchange in multispecies quantum plasmas.

physics.plasm-ph↗

arXiv2020

Effect of Dynamic Ions on Band Structure of Plasmon Excitations

In this paper we develop a new method to study the plasmon energy band structure in multispecies plasmas. Using this method, we investigate plasmon dispersion band structure of different plasma systems with arbitrary degenerate electron fluid. The linearized Schrödinger-Poisson model is used to derive appropriate coupled pseudoforce system from which the energy dispersion structure is calculated. It is shown that the introduction of ion mobility, beyond the jellium (static ion) model with a wide plasmon energy band gap, can fundamentally modify the plasmon dispersion character leading to a new form of low-level energy band, due to the electron-ion band structure mixing. The effects ionic of charge state and chemical potential of the electron fluid on the plasmonic band structure indicate many new features and reveal the fundamental role played by ions in the phonon assisted plasmon excitations in the electron-ion plasma system. Moreover, our study reveals that ion charge screening has a significant impact on the plasmon excitations in ion containing plasmas. The energy band structure of pair plasmas confirm the unique role of ions on the plasmon excitations in many all plasma environments. Current research helps to better understand the underlying mechanisms of collective excitations in charged environment and the important role of heavy species on the elementary plasmon quasiparticles. The method developed in this research may also be extended for complex multispecies and magnetized quantum plasmas as well as to investigation the surface plasmon-polariton interactions in nanometallic structures.

physics.plasm-ph↗

arXiv2020

Ground State Energy of Hydrogen-Like Ions in Quantum Plasmas

Using the asymptotic iteration method (AIM) we investigate the variation in the 1s energy levels of hydrogen and helium-like static ions in fully degenerate electron gas. The semiclassical Thomas-Fermi (TF), Shukla-Eliasson (SE) and corrected Shukla-Eliasson (cSE) models are compared. It is remarked that these models merge into the vacuum level for hydrogen and helium-like ions in the dilute classical electron gas regime. While in the TF model hydrogen ground state level lifts monotonically towards the continuum limit with increase in the electron concentration, in the SE and cSE models universal bound stabilization valley through the energy minimization occurs at a particular electron concentration range for the hydrogen-like ion which for cSE model closely matches the electron concentrations in typical metals. The later stabilizing mechanism appears to be due to the interaction between plasmon excitations and the Fermi lengthscales in metallic density regime. In the case of helium-like ions, however, no such stability mechanism is found. The application of cSE model with electron exchange and correlation effects reveals that cSE model qualitatively accounts for the number-density and lattice parameters of elemental metals within the framework of free electron assumption. According to the cSE model of static charge screening a simple metal-insulator transition criterion is defined. Current investigation may further elucidate the underlying physical mechanisms in the formation and dielectric properties of metallic compounds.

cond-mat.quant-gas↗

arXiv2019

Energy-Dispersion of Matter Waves in Schrödinger-Poisson Model

The energy dispersion of collective excitations of free electron gas as well as self-gravitating ensemble of uncharged particles is derived using a unified 1D Schrödinger-Poisson model. The energy dispersion of self-gravitating system is shown to lead to unique features which are absent in the case of electrostatic excitations. Current mathematical model of collective particle excitations is shown to gives rise to a novel description of the paradoxical wave-particle duality and many intriguing new collective features due to the scale-dependence effective forces in collective interactions, absent in the single particle description of physical systems. It is shown that the excitations in a self-gravitating system lead to a fundamentally different features of collective interaction under gravitational potential than that of electrostatic ones. Particularly, it is found that the total energy of self-gravitating systems can be negative and the effective mass of excitations vary significantly in the whole spectrum of wavelength. The later may be considered as meaningful absence of self-consistent theory of quantum gravity. The significance of the peculiar aspects of the two fundamentally different excitation types is discussed based on their relevance to modern theories.

physics.gen-ph↗

arXiv2019

Pseudo-Resonance and Energy Band Gap in Plasmonic Crystals

In this paper, using the generalized coupled pseudoforce model with driving elements, we develop a method to study the plasmon excitations and energy band structure in a plasmonic crystal. It is shown that the presence of the periodic ion core potential leads to pseudo-resonance condition in the plasmon wavefunction and electrostatic potential profiles, quite analogous to the frequency resonance, leading to the gap formation in the energy dispersion profiles. It is found that the dual length scale character of plasmon excitations lead to occurrence of a critical value of $a_c=2πλ_p$ for the lattice constant ($λ_p$ being the plasmon wavelength) above and below which the energy band structure of plasmonic crystals becomes substantially different. It is also found that energy band gap positions of parabolic free electron energy dispersion relation are slightly higher compared to that of the plasmon excitations. Here based on the plasmon definition and due to the dual length scale character of plasmons compared to that of single electrons, we provide a simplified interpretation of the wave-particle duality in quantum physics and provide the length scale regime in which both wave and particle properties can be simultaneously examined in a single experiment, where, the complementarity principle breaks down. However, the dual characteristics of electron-plasmon coupled excitations, quite analogous to starling murmuration phenomenon, strongly suggests that the long south de Broglie-Bohm pilot wave of electron is nothing but the plasmon itself. The wavefunction and electrostatic potential solution for a one dimensional plasmonic lattice with a generalized periodic potential is also derived in this research.

physics.plasm-ph↗

arXiv2019

Wavefunction of Plasmon Excitations with Space Charge Effects

The one dimensional (1D) driven quantum coupled pseudoforce system governing the dynamics of collective Langmuir electron oscillations is used in order to investigate the effects of variety of space charge distributions on plasmon excitations of a nearly free electron gas with arbitrary degree of degeneracy and electron fluid temperature. A generalized closed form analytic expression for the grand wavefunction of collective excitations in presence of an arbitrary space charge distribution is presented based on the stationary solutions of the driven coupled pseudoforce system which has been derived from the Schrödinger-Poisson model. The wavefunction and electrostatic potential profiles for some especial cases such as the Heaviside charge distribution, Dirac charge sheet, impurity charge sheet in 1D plasmonic lattice and the Kroning-Penney Dirac charge distributions with particular applications in plasmonics and condensed matter physics is investigated in this paper. It is remarkably found that two parallel Dirac charged sheets completely shield all interior plasmon excitations with any given energy value from outside electrostatic fields and charge densities. It is also found that the presence of even a weakly charged impurity layer within a perfect 1D plasmonic crystal profoundly destroys the periodic electrostatic field of the crystal lattice, hence, the Bloch character of the wavefunction considered in band gap theory of solids. Current investigation of electron excitations in arbitrary degenerate electron gas in the presence of static charge distributions may be used to develop analytic models for a variety of real physical situations. It also helps in further developments of the rapidly growing fields of nanotechnology and plasmonics.

physics.plasm-ph↗

arXiv2018

Characteristics of Plasmon Transmittivity Over Potential Barriers

In this paper we use the Schrödinger-Poisson model to obtain a linear coupled pseudoforce system from which the wave function and the electrostatic potential of the free electron gas plasmon is deduced. It is shown that unlike for single particle wave function the plasmon wave function and corresponding electrostatic potential are characterized with two different wave numbers associated with two distinct characteristic length scales, namely, that of the single electron oscillation and of the collective Langmuir excitations. Interaction of plasmon with a rectangular potential step/well indicates features common with that of the ordinary single quantum particle. However, the two-tone oscillation character of the wave function and potential appear on the transmitted amplitude over the potential barrier/well. The plasmon propagation is found to have a distinct energy gap corresponding to the plasmon energy value of $ε_g=μ_0+2ε_p$ below which no plasmon excitations occur. For instance, the zero-point plasmon excitation energy for Aluminium, is around $ε_0\simeq 41.7$eV at room temperature, with the Fermi energy of $ε_F\simeq 11.7$eV and plasmon energy of $ε_p\simeq 15$eV. It is seen that for plasmon energies very close to the energy gap, i.e. where the two characteristic scales match ($k_1\simeq k_2$), the quantum beating effect takes place. The study of plasmon tunneling through the potential barrier indicates that the transmittivity has oscillatory behavior similar to that of a quantum particle tunneling through the potentials, but, with a characteristic two-tone oscillatory profiles. Current development can have a broad range of applications in plasmon transport through diverse free electron environments with arbitrary degeneracy and electron temperature. It also makes progress in rapidly growing nanotechnology and plasmonic fields.

physics.plasm-ph↗

arXiv2018

Multi-cnoidal Solutions of Korteweg-de Vries Evolution Equation

The N-cnoidal solution of the Korteweg-de Vries (KdV) evolution equation is presented based on the prolongation structure theory of Wahlquist and Estabrook [J. Math. Phys. \textbf{16}, 1 (1975)]. The generalized KdV cnoidal wave solutions satisfying both the evolution as well as the potential equations is obtained and the multi-cnoidal components are extracted from the regular and singular potential components. Current technique for construction of superposed cnoidal waves is the immidiate generalization of the N-soliton solution for KdV using the Bäcklund transformation proceedure. Quite analogous to the linear effect, the nonlinear beating is observed to exist also for nonlinear superposition of two cnoidal waves. It is further found that the nonlinear superposition of cnoidal wave with a soliton alters the whole periodic wave pattern declining the amplitude of the soliton significantly. In a three-wave nonlinear interaction of cnoidal waves it is remarked that introduction of extra cnoidal wave tends to destroy the beating pattern formed by the two of them. Furthermore, the superposition of two solitons with a cnoidal wave results in only one soliton hump traveling with the smaller soliton speed in the periodic background and with the other soliton disappeared. Current findings can help to better understand the nonlinear periodic wave interactions and nonlinear decomposition of the realistic experimental data to its components.

nlin.PS↗