Quantum Screening Effects Research Articles

Laser beam effect on the entanglement of elastic collisions in quantum plasma

In the quantized field formalism, using Kramers–Henneberger unitary transformation as the semi-classical counterpart of Block–Nordsieck transformation, the dynamics of entanglement during the low energy scattering processes in bi-partite systems at the presence of a laser beam fields are studied. The stationary-state Schrodinger equation for the quantum scattering process is obtained for such systems. Then, using partial wave analysis, we introduce a new form of entanglement fidelity considering the effect of high-intensity laser beam fields. The effective potential of hot quantum plasma including plasmon and quantum screening effects is used to obtain the entanglement fidelity ratio as a function of the laser amplitude, and plasmon and Debye length parameters for the elastic electron-ion collisions. It is shown that the plasma free electrons oscillations under interaction with laser beam fields improve the correlations between charged particles and consequently lead to the increase in the system entanglement.

Readout of Quantum Screening Effects Using a Time-Dependent Probe.

In voltage- and temperature-biased coherent conductors quantum screening effects occur if the conductor's transmission is energy dependent. Here, we show that an additional ac-driven terminal can act as a probe for a direct readout of such effects, hitherto unexplored. We find that screening of charges induced by the static biases impacts already their standard linear thermoelectric response coefficients due to nonlinear effects when accounting for the frequency of the time-dependent driving. Those effects should be observable under realistic experimental conditions and can literally be switched on and off with the ac driving.

Influence of dense quantum plasmas on fine-structure splitting of Lyman doublets of hydrogenic systems

Relativistic calculations are performed to study the effects of oscillatory quantum plasma screening on the fine-structure splitting between the components of Lyman-α and β line doublets of atomic hydrogen and hydrgen-like argon ion within dense quantum plasmas, where the effective two-body (electron–nucleus) interaction is modeled by the Shukla–Eliasson oscillatory exponential cosine screened-Coulomb potential. The numerical solutions of the radial Dirac equation for the quantum plasma-embedded atomic systems reveal that the oscillatory quantum screening effect suppresses the doublet (energy) splitting substantially and the suppression becomes more prominent at large quantum wave number kq. In the absence of the oscillatory cosine screening term, much larger amount of suppression is noticed at larger values of kq, and the corresponding results represent the screening effect of an exponential screened-Coulomb two-body interaction. The Z4 scaling of the Lyman doublet splitting in low-Z hydrogen isoelectron...

Plasma Screening Effects on Atomic Collisional Orientation in Quantum Plasmas

The quantum plasma screening effects on the atomic collisional orientation phenomena are investigated for the electron-impact excitations of the hydrogenic ion in quantum plasmas. The excitation probabilities and orientation parameter are derived as functions of the collision energy, impact-parameter, and quantum wavenumber using the semiclassical method and effective interaction potential. It is found that the influence of quantum plasma screening enhances the atomic excitation probabilities. The detailed investigations on the variation of excitation preference owing to the quantum screening effects are also presented in figures.

Influence of oscillatory quantum shielding on scattering-induced spin-asymmetry and spin-channel preference in quantum plasmas

This paper is devoted to the oscillatory screening effect on the electron scattering spin-asymmetry and spin-channel preference in quantum plasmas. It is found that the oscillatory quantum screening effects enhance the spin-singlet electron-scattering channel, but suppress the spin-triplet electron-scattering channel for the forward and backward scattering directions with increasing wave number for small quantum wave numbers. It is also found that the preference of the spin-singlet scattering, including the influence of oscillatory quantum shielding, has been reduced with increasing quantum wave number. The variation of the angular averaged scattering spin-asymmetry phenomenon is also discussed.

Electron-exchange and quantum screening effects on the collisional entanglement fidelity in degenerate quantum plasmas

The influence of electron-exchange and quantum screening on the collisional entanglement fidelity for the elastic electron–ion collision is investigated in degenerate quantum plasmas. The effective Shukla–Eliasson potential and the partial wave method are used to obtain the collisional entanglement fidelity in quantum plasmas as a function of the electron-exchange parameter, Fermi energy, plasmon energy and collision energy. The results show that the quantum screening effect enhances the entanglement fidelity in quantum plasmas. However, it is found that the electron-exchange effect strongly suppresses the collisional entanglement fidelity. Hence, we have found that the influence of the electron-exchange reduces the transmission of quantum information in quantum plasmas. In addition, it is found that, although the entanglement fidelity decreases with an increase of the Fermi energy, it increases with increasing plasmon energy in degenerate quantum plasmas.

Electron-exchange and quantum screening effects on the Thomson scattering process in quantum Fermi plasmas

The influence of the electron-exchange and quantum screening on the Thomson scattering process is investigated in degenerate quantum Fermi plasmas. The Thomson scattering cross section in quantum plasmas is obtained by the plasma dielectric function and fluctuation-dissipation theorem as a function of the electron-exchange parameter, Fermi energy, plasmon energy, and wave number. It is shown that the electron-exchange effect enhances the Thomson scattering cross section in quantum plasmas. It is also shown that the differential Thomson scattering cross section has a minimum at the scattering angle Θ=π/2. It is also found that the Thomson scattering cross section increases with an increase of the Fermi energy. In addition, the Thomson scattering cross section is found to be decreased with increasing plasmon energy.

Influence of the Dynamic Quantum Shielding on the Transition Bremsstrahlung Spectrum and the Gaunt Factor in Strongly Coupled Semiclassical Plasmas

The influence of the dynamic quantum shielding on the transition bremsstrahlung spectrum is investigated in strongly coupled semiclassical plasmas. The effective pseudopotential and the impact parameter analysis are employed to obtain the bremsstrahlung radiation cross section as a function of the de Broglie wavelength, Debye length, impact parameter, radiation photon energy, projectile energy, and thermal energy. The result shows that the dynamic screening effect enhances the transition bremsstrahlung radiation cross section. It is found that the maximum position of the transition bremsstrahlung process approaches to the center of the shielding cloud with increasing thermal energy. It is also found that the dynamic screening effect on the bremsstrahlung radiation cross section decreases with an increase of the quantum character of the semiclassical plasma. In addition, it is found that the peak radiation energy increases with an increase of the thermal energy. It is also found that the dynamic quantum screening effect enhances the bremsstrahlung Gaunt factor, especially for the soft-photon case.

Paradox of low field enhancement factor for field emission nanodiodes in relation to quantum screening effects

We put forward the quantum screening effect in field emission [FE] nanodiodes, explaining relatively low field enhancement factors due to the increased potential barrier that impedes the electron Fowler-Nordheim tunneling, which is usually observed in nanoscale FE experiments. We illustratively show this effect from the energy band diagram and experimentally verify it by performing the nanomanipulation FE measurement for a single P-silicon nanotip emitter (Φ = 4.94eV), with a scanning tungsten-probe anode (work function, Φ = 4.5eV) that constitutes a 75-nm vacuum nanogap. A macroscopic FE measurement for the arrays of emitters with a 17-μm vacuum microgap was also performed for a fair comparison.

Influence of the oscillatory quantum screening on the occurrence scattering time in electron-ion quantum plasmas

The oscillatory quantum screening effects on the occurrence scattering time advance for the electron-ion collision are investigated in dense quantum plasmas. The eikonal method is applied to obtain the scattering amplitude and occurrence scattering time advance for the electron-ion collision in quantum plasmas. The result shows that the oscillatory screening effect suppresses the occurrence scattering time advance for the electron-ion collision in quantum plasmas, especially, for large scattering angles. It is also found that the oscillatory screening effect on the occurrence scattering time advance increases with an increase of the collision energy.

Oscillatory quantum screening effects on the positronium (Ps) formation in quantum plasmas

The oscillatory quantum screening effects on the positronium formation by the positron are investigated in quantum plasmas. It is found that the oscillatory screening effects suppress the positronium formation radius as well as the positronium formation cross section. It is also found that the positronium formation radius decreases with increasing quantum wave number. It is found that the peak position of the differential cross section is receded from the projectile with decreasing quantum wave number. In addition, the oscillatory screening effects on the positronium formation cross section are found to be decreased with an increase of the collision energy.

Magnetic field and quantum screening effects on the occurrence time advance in quantum magnetoplasmas

The magnetic field and quantum screening effects on the occurrence scattering time advance for the electron-ion collision are investigated in quantum magnetoplasmas. The result shows that the occurrence scattering time advance decreases with an increase of the magnetic-field strength. It is also found that the occurrence time advance decreases with increasing projectile energy and increases with increasing scattering angle. In addition, the occurrence time advance decreases with an increase of the quantum effect, i.e., Fermi wavelength.

Oscillatory quantum screening effects on the transition bremsstrahlung radiation in quantum plasmas

The oscillatory screening effects on the transition bremsstrahlung radiation due to the polarization interaction between the electron and shielding cloud are investigated in dense quantum plasmas. The impact-parameter analysis with the modified Debye-Hückel potential is applied to obtain the bremsstrahlung radiation cross section as a function of the quantum wave number, impact parameter, photon energy, and projectile energy. The results show that the oscillatory quantum screening effect strongly suppresses the transition bremsstrahlung radiation spectrum in dense quantum plasmas. It is also found that the oscillatory quantum screening effect is more significant near the maximum peak of the bremsstrahlung radiation cross section. In addition, the maximum peak of the bremsstrahlung radiation cross section is getting close to the center of the shielding cloud as increasing quantum wave number. It is interesting to note that the range of the bremsstrahlung photon energy would be broadened with an increase of the oscillatory screening effect. It is also found that the oscillatory screening effects on the transition bremsstrahlung spectrum decreases with increasing projectile energy.

Quantum Screening Effects on the Entanglement Fidelity for Elastic Collisions in Electron-Ion Quantum Plasmas

The quantum screening effects on the entanglement fidelity for the elastic collision are investigated in electron-ion quantum plasmas. The partial wave analysis and modified Debye-Hückel interaction potential are employed to obtain the entanglement fidelity function in electron-ion quantum plasmas as a function of the collision energy, charge of the ion, and quantum wave number. It is found that the quantum screening effects significantly enhance the entanglement fidelity in electron-ion quantum plasmas. It is also found that the entanglement fidelity increases with an increase of the ion charge. The quantum screening effects on the entanglement fidelity is also found to be increased with increasing plasma density. In addition, it is found that the quantum screening effects decreases with an increase of the collision energy.

Quantum screening effects on the ion-ion collisions in strongly coupled semiclassical plasmas

The quantum screening effects on the ion-ion collisions are investigated in strongly coupled semiclassical hydrogen plasmas. The method of stationary phase and effective interaction potential containing the quantum mechanical effect are employed to obtain the scattering phase shift and scattering cross section as functions of the impact parameter, collision energy, de Broglie wavelength, and Debye length. The result shows that the scattering phase and cross section decrease with increasing de Broglie wavelength. It is also shown that the scattering cross section increases with an increase of the Debye length. Hence, it is found that the quantum effect suppresses the scattering cross section. In addition, the quantum effect on the scattering cross section is found to be more important in small Debye length domains.

Quantum and plasma screening effects on the Wannier threshold law for the double-electron escape in strongly coupled semiclassical plasmas

The quantum and plasma screening effects on the Wannier threshold law for the double-electron escape are investigated in strongly coupled semiclassical plasmas. The renormalized electron charge and Wannier exponent are obtained by considering the equation of motion in the Wannier configuration with the screened pseudopotential model as functions of the de Broglie wavelength, Debye length, and charge of the residual ion. It is shown that the renormalized electron charge significantly increases with an increase in the de Broglie wavelength, especially for small radial distances. It is also shown that the quantum effects enhance the Wannier exponent for the double-electron escape. In addition, the quantum effect on the Wannier threshold law is found to be more important than the plasma screening effect in strongly coupled semiclassical plasmas.

Charge degeneracy for a Thomas–Fermi hydrogen molecule: Bound–unbound transition

We study the relationship between quantum screening effects and charge symmetry in the hydrogen molecule. In this model, the charge symmetry of the molecule is broken in the presence of the Thomas–Fermi potential exp ( − q r ) / r . We argue that screening acts as an external field that promotes charge degeneracy in the system. In the presence of screening ( q ≠ 0 ), the charge symmetry of the H 2 + molecule is broken and thus the effective nuclear charge α splits into two, α → ( α , γ ) , where γ is the dual charge. The effective nuclear charge α is then related to the binding energy of the electron, while the dual charge γ is responsible for the screening effect in the wavefunction. Naturally, both the energy and the wavefunction are modified by this charge degeneracy. We obtain an analytical formulation for the molecular energy with a charge degeneracy effect. To test the efficiency of our model, we analyze the behavior of the molecule’s energy as a function of the Thomas–Fermi parameter q and calculate the critical parameter q ∗ , as well as the critical dual charge γ ∗ for which the bound–unbound transition occurs. We observe an interesting super-freezing screening phenomenon for the Thomas–Fermi hydrogen molecule.

Quantum and plasma screening effects on electron–hydrogen polarization transport collisions in partially ionized plasmas

The quantum state and plasma screening effects on electron–neutral atom polarization transport collisions are investigated in partially ionized hydrogen plasmas. The screened Buckingham potential model is applied to describe the polarization interaction between the projectile electron and the neutral target atom in partially ionized plasmas. The method of partial waves is applied to represent the electron–atom polarization transport cross-section as a function of the quantum states, Debye length and collision energy. The results show that the plasma screening effects on the polarization transport cross-section are found to be more significant for low collision energies. It is also found that the transport cross-section is significantly increased with increasing quantum states.

Quantum screening effects on orientation phenomena in strongly coupled semiclassical plasmas

The screening and quantum effects on the orientation phenomena ( L ⊥ ) for the 1 s → 2 p ± collisional excitations in strongly coupled semiclassical plasmas are investigated. It is found that the 1 s → 2 p −1 transitions are strongly favored in all impact parameter regions. The preference of the 2 p −1 excitation increases with decreasing the thermal de Broglie wave length and decreases with increasing the collision energy. The quantum and screening effects on the orientation parameter are found to be increased with increasing the projectile energy. It is also found that the orientation parameters have minima which correspond to the complete 1 s → 2 p −1 transition since the 1 s → 2 p +1 transition probability is quite small for small impact parameters.

Interference Effects on Electron Collisions in Strongly Coupled Semiclassical Plasmas

The quantum interference and plasma screening effects on elastic electron collisions are investigated in strongly coupled semiclassical plasmas. The effective pseudopotential taking into account both the screening and quantum effects is applied to represent the electron-electron interaction in strongly coupled semiclassical plasmas. The Born analysis and the total spin states are considered to obtain high-energy electron-electron scattering cross sections. The results show that the scattering cross sections are significantly reduced with increasing quantum screening effect. The quantum effect is found to be more important than the plasma screening effect. It is also found that the quantum interference effect is especially important at the scattering angle θ = π/4.